My opinion... if the liquidity exists to support it, buying pressure on the STEEM price plus burning STEEM would be far superior to just burning SBDs. It's applying two different forms of favorable pressure. And, as long as STEEM is priced below the haircut threshold, the SBD price should rise organically if the STEEM price rises, so the selling pressure on that side shouldn't matter at all.

To me, the only conceivable drawback is that burning STEEM would raise the haircut price. (Maybe it's worth burning a mix of both to hold the haircut price constant?)

BUT, I would only support it with a strong community control on the account that's buying the STEEM. Over the years, I've seen too many rug pulls from anonymous accounts who promised to do good things with funds that they collected. I will never again support initiatives like that without some oversight capability.

If we can't have some sort of technological or legal guarantee that the funds will be used as expected, I'd rather just keep burning SBDs to get the haircut price down to a reachable level. That requires 0 trust.

(FTR,compared to BTC and HIVE, STEEM has been holding steady, or even gaining, and the SBD price is still tracking the haircut ratio. So, I'm fairly confident that the burn initiative is not causing any price declines. IMO, those prices are just dropping with the broader market.)