Try the Yahoo User Group, there are a lot of questions answered there. The author of the program can probably tell you more than you'd ever want to know about it, and he's on that forum.
Sure, APRS can certainly be useful, but as already said, it's not -the- 'cure' for just a whole lot of things. There are quite a few commercial applications of the same thing that are just as useful if not more so. It can be interesting though, and that's enough reason for some people, not for others. I think you can say that about a lot of 'modes', not just APRS.
And then there are those, who for whatever reason, just don't care to 'advertise' their location all the time, or ever, for that matter.
I got into it for a few reasons, some more 'important' that others. Also because others I am
associated with are doing it, and because I think it's interesting (and challenging). I have a personal use for it too. It's not for everyone.