> why does it make more sense to use asts here

For one, it eliminates a class of merge conflict that arises strictly from text formatting.

I always liked the idea of storing code in abstraction, especially editors supported edit-time formatting. I enjoy working on other people's code, but I don't think anybody likes the tedium of complying with style guides, especially ones that are enforced at the SCM level, which adds friction to creating even local, temporary revisions. This kind of thing would obviate that. That's why I also appreciate strict and deterministic systems like rustfmt. Unison goes a little further, which is neat but I think they're struggling getting adoption because of that, even though I'm pretty sure they've got some better tooling for working outside the whole ecosystem. These decoupled tools are probably a good way to go.

I was messing around with a file-less paradigm that would present a source tree in arbitrary ways, like just showing a individual functions, so you have the things you're working on co-located rather than switching between files. Kind of like the old VB IDE.