Burning stables have no inherent benefits to their holders. It's not like there are intrinsic benefits to being a holder of both so I have absolutely no reason why they didn't just use the table coin to buy bitcoin and destroy those bitcoin rather than just burning stablecoins that does nothing for the greater good. Good move for the wrong reasons.
There are two reasons why they won't do what you suggested. One is because stablecoin doesn't have the interest of Bitcoin at hand, so they won't benefit from anything by buying and burning bitcoin. Secondly, they are removing excessive dust with that burning (at least that's what they want us to believe) so spending the coin instead of burning it can make the supply to be above the physical locked dust which is supposed to be keeping the value on 1-1
That's exactly my point. There will be no inherent benefits to bitcoin or even stablecoins for that matter of they choose to burn USDT or USDC. The notion of burning tokens stems from the fact that burning tokens means less supply but more demand have no benefits for stablecoin holders since it's always 1:1. They will do a lot of good if they just use the proceeds to buy bitcoin or sponsor some of the core researchers that put in serious work to continue bitcoin research.