You can write git in any language, I don't see an advantage doing it in Rust besides the community and potential of promotion to that community.

You can write any program in any language, but there are definitely benefits of using some languages for some programs. If you disagree with this statement, there's nothing else to discuss, we have irreconcilable differences.

You just responded to a comment giving a specific advantage that applies to Rust and a few other languages which doesn't apply to a large amount of other languages (single static binary).

How can you still not see any advantage? Or was the point of your comment to say that you think the only real motivation is self or Rust promotion, suggesting some dishonesty amongst the people you're responding to?

Sure, but we're talking about a git web UI with a little icing, not a git replacement (at least in most cases). Even so, Rust and Go web projects are much more lighterweight than projects in most other languages, with drastically less effort towards performance, and use less resources as a result, requiring less hardware to operate.