Doesn’t Git store data in sparse files? My impression is that git’s on-disk layout is exactly the kind of thing you’d avoid on object storage. Interactions involve a ton of small reads, resulting in poor performance and enormous bills.
It only really makes sense to tarball repos into cold storage on S3 or Glacier, but short of GitLab cloud I suspect there aren’t enough repos cold enough to be worth the dev costs.
S3 that doesn’t have wild costs for git objects sounds like it’s just NFS