The "absurd payload size" is the effect of having at least four different SDKs (macOS, watchOS, i[Pad]OS, tvOS) bundled, including a simulator for three of them.
Xcode 15 is a ~3.5 gigs download, and includes only macOS SDKs, with all of the other (including the visionOS SDK + sim) ones being downloaded on-demand.
- using App Store for Xcode was historically very painful and ~nobody who uses Xcode daily downloads it from MAS
- it never worked ~that well~ for Xcode anyway - apart from the big download sizes, the problem with Xcode and the bundled SDKs is that they’re all approximately trillion little text files, and it’s not unheard of to wait longer for codesign (technically unxip) verification than for the download itself, which negates the user-facing benefits of delta upgrades for many users.
I've been doing this for as long as it's been available there as a developer at Apple, in my own startup, and in my current role as well. Never had a problem with it.
Before that though I used to only install command line tools.
At some point though, I forgot the incantation for it and realized I could just use Nix for git as I was using it for other things already.
Unfortunately, as the git website [1] states, these are fairly out of date (currently 2.33 from 2021-08-30). To get something recent, you have to build them yourself, which requires...devtools.
Seems bizarre, to me, that they don't have them built automatically.