Well, firstly, stow existed long before git, so some of it might just be "don't break what isn't broken".

In the 90's, I worked at a place that had DEC Alphas with OSF/1, Sun UltraSPARCs with Solaris, x86 Linux boxes, and a few random SGI, HP, *BSD boxes and so on. The commercial Unix variants come with a fairly limited set of programs. So that we had a useful environment, no matter what machine was being used, we had a large tree of FOSS NFS-mounted onto each box.

That tree used a shared source tree, build trees for each machine-os platform, and then we stowed the built stuff.

Stow was mostly useful when uninstalling (because not everything had a reliable `make uninstall` option), or to quickly switch between active versions.

I don't think I'd attempt to put that whole thing into git today: stow is the right tool for the job.