That is a great question. I personally always buy steem with sbds earned. Steem is my first venture into the world of cryptos, a personal experiment. I do not need the earnings, meager as they are, to live. My thinking is this, if I can grow the amount of Steem, perhaps someday it can provide another source of income. If Steem crashes tomorrow, it doesn't really matter because I have enjoyed my time sharing thoughts and ideas with everyone here. If on the other hand 5-10 years from now, all the early adopters are sitting back on a small fortune because the steemit platform has replaced Facebook, Youtube and Ebay, then huge bonus for those who continue to power up.