OP: you are forgetting: it's fun. there's a lot of people that love the idea of an internet currency. it's very fun. that alone makes it worth something. it's rare. people still seek old baseball cards. etc, etc, think outside the box!
Maybe because they find bitcoin as a good source of profit they buy bitcoin to make some investments. And ofcourse to double or triple their investments its true it may take a long term but if its really worth the wait there is no need to rush things