I agree, I don't think that a bug in GCC last millennium is a very strong argument for using Rust instead of C today, though such arguments do exist.

However, I also don't think they particularly help you to distinguish a compiler bug from an error in your understanding of the language semantics, although they sure do help a lot with everyday errors.

With respect to questions of inferiority or superiority, keep in mind that Valgrind and UBSan are only dynamic checkers; they don't help at all with errors that don't occur in your testing. Frama-C is a static checker more similar to Rust's capabilities, but much more limited, but also with cscope-like abilities for reverse-engineering existing source bases.

The great advantage these three tools (and ASan) have is that you don't have to rewrite your C in Rust in order to use them.