That does sound great, but to be fair most of the time, the helm equivalent is to type one or a few more characters of the one file name you want and press enter. Avy is a great tool, but in my experience using C-s actually requires fewers strokes than Avy over 90% of the time. Being limited to whatever is on screen tends to get very annoying, as is the mental load of pressing random characters instead of completing a word you already know. For me Avy shines for things like avy-copy-line that can prevent you from moving back and forth.