I've supported Burnpost since day one. It definitely signals for significant changes so burnposts are no longer required

It doesn't, up until now, signal much because its participation has been low (1-2% of reward pool). Even back when SBD was radically overvalued meaning that 1 STEEM sent to burnpost in liquid rewards would buy 10-15 STEEM from the market and then reduce inflation by 10-15 STEEM, it still only had very small participation (albeit slightly higher than when that clear 'bonus' went away).

Possibly the EIP changes making direct milking more difficult will increase participation and build stronger signal to lower inflation. I have noticed some of the vote-selling bots starting to use their extra vote power on it. Maybe if you can't just outright reward yourself, it then becomes more attractive as a second choice to at least help protect the value of your investment.