Also true of literally every OS, on the inherited wisdom that separating the config from the actual application allows it to persist through upgrades and reinstalls easily.

There are certainly other ways to do that, but this is how it has been done since forever.

Right but few kbs of config is less of a bother than few hundred megs of deps installed all over the place.

The config and data is iffy situation because you might want to uninstall just to install new version, and so might want them to stay, might want them gone.