Great suggestion! Until then, think of it this way...
 
You have a band with a drummer, bass player, and rhythm guitar player. You're the conductor. You count down and cue the drummer - the drummer starts playing a riff. Then a couple measures later, you cue the bass player and the bass player starts playing along with the drummer.
 
After they're cookin,' then you cue the rhythm guitar player and now you have the rhythm section working away. Start singing or playing lead on top of the groove...that's one way to think of Matrix view, where each one of those players is a loop.
 
Now, it gets more interesting.
 
You can trigger multiple combinations of loops in different rows to start at the same time. So now let's get back to our rhythm section. At one point in the song it modulates up a semitone. If you have a row with riffs where they're all playing a semitone up, you can trigger that row and they'll all start playing a semitone up.
 
Years ago someone asked me to explain Ableton Live. He worked for GC and was responsible for selling Live, but he played guitar, and thought loops made absolutely no sense. So I said "hey, you're a guitar player, of course you know all about loops." He looked at me like I was crazy. "Hum the first two bars of 'Brown Sugar,'" I said. He did. "Okay, now hum the next two bars." He did that too. "Now hum the next two bars" and he saw what I was driving at...Keith Richards was looping!
 
So I said "Copy the Live manual and do a find-and-replace. Every it says 'loop,' substitute 'riff.'" The Matrix view uses the same kind of thinking.
 
 

The Matrix View chapter from "SWA Complete SONAR X2" is on YouTube. This is one of 50 chapters of that set, done by FastBikerBoy, and is a good overview.
 
Unfortunately, there is not a good substitute for "going in and poking around." It wasn't until I grabbed an old project I wanted to redo that I forced myself to try it out, and was not until then that I could fully understand its capabilities and limitations.

I like the Matrix view in principle and I've used it on a few tracks, but not enough to feel like I have a particularly fluid level of knowledge or control. I kind of relate more to the 'blocks' setup like in Reason, and wish there were something similar in Sonar - though Craig mentioned something about this above, tantalizingly - something to do with groups, time to go explore I guess. But the Matrix, despite its limitations - I agree that being able to click a cell open and edit its contents somehow directly in place would be the bomb - does offer some interesting possibilities, especially if you map it to a physical controller. I keep meaning to use it some more and see where it takes me... 
 
Edit: whoa. Clip selection groups. Very cool. Never noticed that or used it before, but Craig is right: this could be used very creatively in the kind of rapid, lego-block song construction sense. Some feature possibilities jump out at me immediately - if creating a group it could automatically assign a clip colour for those clips so you could visually see which ones are in a group - the current system of a little black number doesn't exactly facilitate quickly seeing which clips make up a group. Oh well. Feature request time!
 
Edit 2: Seems pretty easy to apply colours to clips manually via the clip inspector, and these will apply to a clip group if one is selected. Not quite as convenient as if it happened automatically, but of course that would probably bug some people so it would have to be a selectable behaviour which adds another layer of complexity. Still. Works a charm for setting up a visual sense of what clips form a 'block' and it's super quick and easy to grab and move/copy those blocks around. Thanks Craig - major workflow enhancement for me!

I must admit that I personally do not rely on "undo" in most programs just because 1) every program is different, and 2) there is not always clarification of what "undo" actually does. I will probably get pounded into the dirt for saying this, but "undo" is a programmed function (and I have enough programs on this machine that I do not to trust it - plus cannot remember every program's efficacy). This is not specifically targeted to SONAR in any way (some programs have truly terrible undo functions).
 
Highlighting things (like clips) and deleting them should have the same functionality in all programs. That way I am performing a very specific action intentionally.
 
As an example... some graphic programs create "undo history" by pen stroke, others by "tool choice"... so imagine the immense surprise to "undo" an entire drawing because of a bad pen stroke without a "redo" key.
 
As gets mentioned often... saving is your ultimate friend... if you save just before a recording, then if the above occurs, you can simply close/reopen the project and it is ready for another pass (just in the off chance that the "unforeseen" occurs).

worstcaseontario
"ever use the Matrix view for songwriting?"
 No, because I have Ableton Live.
 I would love it if the matrix view in Sonar allowed the editting of MIDI clips in the cells. This would allow me to sell Live and use Sonar exlusively, which is something that I would like very much.

Has anyone got experience in building clips in Ableton and then importing them (somehow...I doubt they would drag and drop) into Sonar. One of my frustrations is seeing how easy it is to loop and layer sounds in Ableton (in the videos...) and how messy 'comping' is for layering drum tracks in particular. I've been thinking about taking the leap into Ableton, buying a cheap APC20 or something and getting the light version, to see if I can create basic drum/bass grooves and import them as this is one of the most labor-intensive pieces...I'm reasonably good on a 16-pad controller with playing parts of grooves.