I've never quite figured out what I should use a MATT TRACK for or how to use it. Would appreciate some incite from someone who uses this feature.

See the PDF manual starting on page 467.

The short answer is that matte tracks are used to add alpha channel (transparency) information. The reason for using a matte and not the keying editor is that mattes are grayscale images and clips. As such you can easily edit them, add effects to them, etc. If dealing with media taken from film, you may receive matte clips for compositing along with the regular clips.

Take a look at this tutorial.

For other tutorials, click here.

Now I get it...great tutorial