By the times of 2014/2015, burning bitcoin was happening more frequently per this community members' posts (by sending to a specific BTC addy, its privatekey was not at all generated). I mean burning is a known process for the attempt of increasing the value of circulating supply.

If you notice, binance is actively into burning BNB regularly (they have monthly schedule for burning process if I remember correctly); which might be trigger for many devs to have burning as a part of their roadmap.

Moreover, do not get deceived by burning plans. When a coin/token is not backed by "all the requirements of an ideal coin" then burning plans will not bring any changes to it. It may get dumped regularly regardless of whatever amount of circulating supply is burnt.