1) Several reasons, but at its most basic, it (and fishing) is one of the few things I can completely do by myself that is enjoyable and rewarding.

2) Originally got into BP solely for the extended season in VA that normally coincides with the rut. Now I do it almost exclusively. I like the one shot/one kill mentality. Still occasionally use my dad's .308, but if I could use only one rifle all the time, it would be my Omega X7

And regarding the "ego" argument, I don't buy it. Maybe if the deer were scarce but in my neck of the woods they're not. Rarely do I get my allotted 6 per season, but I do fill my freezer and give the rest to friends or the Va Hunters for the Hungry organization which I view as a very worthy cause. I have quite a bit of skepticism for most that claim they hunt solely for the meat as there are usually cheaper ways to put food on the table. Face it, we all have a little bit of ego involved with our hunting choices.