Bluesky also does this, as you type your rich-text left-wing opinion the client builds a parser-optimized metadata thing that gets published together with your post and it gets published as plaintext + this thing attached so it gets easy on the render side to display.

Here on Nostr we like to think we're smart but here we have some of our best client developers wanting to do more and more fancy parsing on the render flow, slowing everything down, and then publicly shaming other clients into doing the same.