To me the matrix view is ideal for creating bump music for broadcast. Typically I will construct a set of loops and one shots that will provide anywhere from 30 seconds to 2 minutes of of audio. This is great for creating music for video transitions and moving from different segments in any online broadcast.
I like this approach because it is quick and fast. I don't need to set up and record guitars or drums. I just use the loops and one shots I collected from cakewalk over the years. This is a fast and great way to provide audio for transitions in your videos.
Usually I will use enough loops and one shots to create about 7 or 8 different segments of bump music from one matrix project. I will have about 15 columns but I keep about 2 or 3 columns of loops per song. Then I set up two or three tracks at a time when I record the matrix loops.
I have also experimented with recording a song using the matrix. After the loops were constructed I would record about three or four columns. Then I would go back and record a few more columns on top of that.
My favorite thing about the matrix view is once you get it down it becomes very quick to assemble something on the fly.
As far as dynamic builds or swells in a song, If I can't find a loop that works I will usually overdub something later if I need too. The combination of using the Matrix view to record and also recording regular tracks works very well.