It's both.  I find Bitcoin interesting as a new idea which I believe will become more popular over time so it's great that a hobby can make money in itself.  But of course I think that when Bitcoin is more popular and is adopted in stores I'll spend it more (of course I will spend it in places that accept it, but that's not many).  You could also even view that future purpose as being fun - money might not buy happiness, but to some extent it does, especially when it's as convenient as Bitcoin.

Bitcoin could be so great for traveling and that would be fun.  Imagine going around the world, not having to convert into any local currencies, only having to take your phone with you and you could pay for anything.  So the future purpose could even be fun in itself.