Some even convert their salary from their job into bitcoins simply because they truly believe in it. There's just no other investments out there that have grown as much as bitcoin. Maybe there are in the stocks world but those aren't really that available for everyone unlike bitcoin. I think that's also one of the reasons why you should not spend your bitcoin unless it's a necessity. Bitcoin is available for everyone and eventually everyone will be using it. Maybe not really everyone, but most people. The more people enter the bitcoin world, the more value bitcoin gets and that makes it harder for us to earn bitcoins. Back then, you can earn 1BTC a month from signature campaigns but you see the rates are nowhere near that these days.
Save as much bitcoins, maybe even get as much bitcoins as you can. It can be a lifesaver for us financially.