Doesn't being under $HOME make .local redundant? I guess one could argue for binaries going in an architecture-specific subdirectory if $HOME was on a shared filesystem, but that's not what's being done here.
To me, $HOME/.local/share and its siblings are just a needless level of indirection, forcing me to jump through an extra hoop every time I want to access what's in there.
(I know it's sometimes possible to override it with an environment variable, but the predictably spotty support for those overrides means I would then have to look for things in two places. I think sensible defaults would be nicer.)
This would match the more recent $HOME/.var that's in widespread use via Flatpak.
It is Microsoft thing. You must pollute the user's /home as much as you can. Can i say that i have 3 daemons on my computer respobsible for ... credentials. This is the way to go.
So if that was their reasoning, it reinforces my view that they didn't think their design through very well.