Groove Clips - what are the downsides?

I am looking at the Groove Clip function. There seem to be a lot of good reasons to use. Any downsides? Why not just use them by default for all clips?
 
And is there any way to do that - set Sonar X3 so that any clip I create is a Groove Clip to start?

Right, its a cool feature with no downside. 

There's no default setting that I'm aware of to do this.

I would recommend not converting a clip to a groove/acidized clip (they're the same thing) unless you need to change tempo or pitch. And if you do, bear in mind that converting to a groove clip does not always stretch optimally - in fact it rarely does. To me the incredible advantage SONAR offers over all other programs other than Sony Acid is that not only can it can read acidized files (most programs can do that), but after conversion to a groove clip you can edit it for optimal stretching.
 
Some DSP/editing functions don't apply to groove clips. For example you can't use Melodyne on one, you have to convert it back to WAV anyway.
 
Bottom line is I love groove clips and use them all the time, but converting regular clips to groove clips when not necessary won't help, and could hurt.
 

Audio that's beyond the start and/or end points of the audio you've selected to turn into a groove clip.

The biggest issue with groove clips is that the length of the clip is almost always calculated incorrectly.
If your original clip is 16 beats ( 4 measures @ 4/4) be sure the groove clip is also 16 beats. More than likely it is not.
MIDI groove clips are generally ok. It's that audio clips that get flaky.
Speeding up the clips is generally fine. Slowing them down is another story. You can go about 15% before artifacts set in. Beyond that, the effect is fairly horrendous, and you  are better off retracking.
That said, I do like groove clips. You just need to be aware of what is happening.

Thanks for all the feedback.