Only been on this site for a minute but I've already seen some of the cool things people have made with more freedom to format things creatively. I'm sure some eye searing horrors will get made, but that's the price of just being able to do more stuff, and hey, if it's a problem, you can always just not look at those posts.
But I think I respect the "trust the people you follow" approach over the "entire site has only the least interesting, most basic tools for expression."
I've gotta admit, I'm so birdsite brained at this point, it feels wild to even be able to just use italics.
One thing that I think might be undersold here is that a lot of people ended up using Unicode special characters to force what creative text emphasis they could out of other sites, like monospace, bold, super/subscript, etc. This has always famously been bad for screenreaders. Here, you can just do those things using plain text and basic formatting which just eliminates that issue and correctly provides more useful information to screenreaders, because now they know something is underlined or emphasized rather than just a string of unpronounceable Unicode...
It feels like such a small, obvious thing, but I'm honestly excited to see it!