This comment explained to me best the use of SBD and the purpose of its "peg". Thank you for that.
So it's a supplementary currency to that of Steem. But what is its purpose if you keep getting Steem anyway? So that if the whole market crashes, you could fight off the "inflation" and get the current $worth of Steem for half your earnings? I guess.
But I really don't see how people could expect it'd never go up.