[oleganza]

That's a valid point. However, modern hardware and crypto algorithms are fast enough that it pays off to have "do it all" protocols, with as little tradeoffs as possible.

Example: Git users do need both corruption protection AND secure authentication. If authentication is not built in, it will have to be built around. Building around is always going to be more costly in the end.

Unfortunately, 20-30 years ago considerations such as "sha1 is shorter + faster" were taken seriously, plus all the crypto that existed back then sucked big time. Remember Snowden scandal in 2013? That, plus Bitcoin and blockchains moving towards mainstream brought about review of TLS, started SHA-3 competition. Many more brains turned to crypto since then and the new era began.