auto is a historic artifact for porting code from the B language to C, when everything was implicitly int but int did not exist yet. It had absolutely no use afterwards, which is why it was repurposed in C++ as well. In C23 this is done because it is very useful in combination with typeof() in macros, which is a far cry from SFINAE terrorism in C++
I have never seen anyone use auto in code newer than the mid-70s, apart from C++ programmers accidentally using it in a case where it happens to work.
In the 1980's it was still around in compilers that were K&R C subsets for 16 bit home computers.
It used to be in c++ too and I have never even heard of a conflict this caused