First of all thank you for the mention.. i still believe that SBD will come down to 1$ price for which it was intended...

Its good that you already know that sbds get destroyed..

Once upon a time, steem price fell to 0.07$ and it was driving the entire platform into the ground. So at that time, SBDs were created and they were pegged to 1USD to provide stabilitiy to platform..

You can choose your payouts to be delivered half in SP and half in SBDs. You can use the SBDs to do many things like buy stuff from market place, buy upvotes from bots etc..

Now coming to your point that why steemit price is above its pegged value.. (its because of high demand). And voting bots are to be blamed for this.. people today are now so much used to buying an upvote from bot (including you and me both), that we cannot stand the idea of our post going into the hole with 1.5$ tag on its neck. So it is us who keep the demand high of sbd due to which, there is always a pump on exchanges.. due to its stability and high demand, sbds remain on pumped value.

Witnesses have tried several means to restrict the price of SBD yet they could not bring it down to its original value.

As per my estimation, value of SBD has not decreased from 2.5$ value. The vakue you are seeing right now (1.8$) is because of overall market correction and low bitcoin prices..

Hope this long reply will clear a lot of doubts in your mind... if you have further queries, do respond..

P.S. I am self voting this comment for visibility..