I kind of have to agree with the guy there, it would be kind of trash if everyone just inlined assembly instructions. Manual SIMD already feels a bit like cheating. Ideally, there should be two solution categories, idiomatic solutions and optimised solutions. I would prefer if the idiomatic solutions matched what the average programmer would write.

I think we worry about performance far too much when choosing a language. However, when performance is important, it's important to recognise the different classes of languages, say {Go, Rust, C} vs {Python, JS, Ruby} in terms of speed and memory footprint vs productivity.