Because Bitcoin is very interesting project, and I like the fact I dont need middleman to be able to pay with Bitcoins - it mean responsibility to keep my coins safe though (but it is usefull skill for everyone 
).
).keeping the coins safe is actually a pain, to be honest. I think when the banks realize the importance of bitcoin and start to embrace it, we'll deposit bitcoin into the banks. The bank just has to find other ways to make money