Lately there has been discussion around SBD which should be a token pegged to US dollar. The peg hasn't been holding very well. The situation isn't catastrophic because the error has been in the upper side (SBD is worth more than one dollar), but the system is still broken, nonetheless.
Root cause is the fact that the amount of SBD doesn't change according to the supply and demand of the markets. There has been a lot more demand for SBD so the price has gone way too much up. If the Steem blockchain can't print more SBD when there is more demand, the peg won't hold.
But if the blockchain starts to print more SBD, there is a systemic risk. If the price of steem goes down, the liability for backing the SBD token will be much bigger.
The usecase for a stable cryptocurrency is to help normal people to use it as a currency. Most people aren't interested in using very volatile currency in daily activities. SBD was supposed to help with this. But so far we haven't seen market places or any other real usecases for SBD although it has been existed for more than a year.
So we have two facts that speak against SBD: it can't hold the peg, and pretty much nobody is using it for what is was created for.
And here his a third. A while ago 
The dollar sum indicating how much a post has earned goes down when the price of steem goes down. I think we have now pretty good evidence that when users see dollars, they think in dollars. They forget that they earn also steem tokens which will become more valuable if the demand goes back up someday.
The funny thing is, those successful authors who left the platform when the price went down, would have multiplied the value of their earnings if they had stayed and taken their rewards in SP instead of SBD.
But they didn't do so. Why? Because the dollar amount in the posts is so misleading. It's depressing to see it go down.
The solution is simple: Ditch the SBD and start paying rewards only with steem and SP.
When there is no dollar amount in the posts but steem amount instead, it doesn't change everyday depending on volatility of the price. What you see and get is the amount of steem that you are rewarded by the upvotes. That is more accurate showing you if you have been successful because you write so well. Currently authors can have a fake feeling of success just because they wrote their piece when the price of steem was high which made the dollar amount big.
Now you could be developing as writer and become more successful in here, but you don't really see and feel that because your rewards depend more on the price of steem than your writing abilities and popularity.
When users start to think in "reward points" (in this case steem tokens) rather than dollars they will become much more engaged. They don't get discouraged just because cryptocurrency markets happened to go down when they wrote a few good posts.
Because I don't see any good reasons to have stable cryptocurrency on this platform, I suggest we remove it. It will make the user experience better, remove unnecessary systemic risk and make the system overall simpler.