From this, it seems clear to me that investors should encourage the burning of SBD through the use and expansion of the promoted post feature by authors, curators, and developers.

Maybe this is just semantics, but I think it's a mistake to call this "burning". It's really unclear to me if burning, in-and-of-itself, actually does anything good for a token. You could even make the case that someone burning a token is sending a signal to the world "This is worth $0". But the promoted post feature isn't necessarily doing that, it's you buying something from the blockchain, so the signal is "Having extra visibility is worth X SBD to me".

As I understand it, the usual argument in favor of burning is the assumption that overall market cap represents the total valuation, so eliminating some tokens from the supply should increase the price because overall valuation won't change. The analogy is presumably a stock buyback (or maybe some things that central banks do). But I think the key there is the buy in the buyback, the price goes up because there are buyers in the market. So sure, the thing disappears from the market, but I wonder if that's more of a side effect than a causal factor. (If we wanted something similar, with a central agent buying tokens and disappearing them, a DAO-funded bot could do that).