It's worth noting that HPC is a different problem space from say, kernels, drivers, codecs, and browsers, in that HPC is not generally expecting to deal with adversairial input, and those other spaces are. So the safety-performance trade-off is truly different between you and many of the commentators who are rightly pointing out C/C++'s atrocious track record in the secure space.

Also, I've done a small amount of scientific HPC, and as I see it "correct" is infinitely more important than "fast". If you look at the amount of incorrect scientific papers that trace back to accidentally and silently corrupted data, I think maybe it might sense to consider using any and all possible tools to avoid corruption, of which Rust is but one example (and you've named others like valgrind).