Without knowing anything about @yar’s goals, I’m just going to say out of the blue: time well spent! Rust and Swift are close cousins, time spent learning one helps with the other, understanding their diffs sharpens understand of langs in general, their general “ML + systems + ergonomics” approach is likely to be relevant in many spheres for decades to come, plus they’re both just cool langs. Curiosity is rarely wasted, but especially not here.