These days I'm gambling a lot, so I spend my Bitcoin but you can call it investment too. Because I usually win and get back more coins. I only play for the most possible (guaranteed) bets. If I need something digital I'd use my Bitcoin to buy too.
What are these guaranteed bets that you are talking about? Sports bets, but those are really not guaranteed even if you have a team that is the top, they will eventually lose some time. And you better hope you don't put a lot on them at that time of defeat.