This isn't the right lesson to derive from this. These benchmarks show that the high performance cores pack a lot of smarts which can maintain high performance

This isn't the right lesson to derive from this. These benchmarks show that the high performance cores pack a lot of smarts which can maintain high performance with idomatic Swift. Idiomatic Swift is still great for code which doesn't have significant performance consequences and/or is likely to only ever run on the Firestorm cores—i.e. any user-interactive process. If you're writing a background task which is expected to have some non-negligible load on the CPU, it could make sense to experiment with simpler C-style coding for the hottest loops in your code.