To be fair, at least when I tested it on a moderately sized codebase, ty was definitely faster than Pyrefly. Like twice as fast (0.5s vs 1s, give or take). However, it's not really critical to save that half a second for full checks. Both have gradual checking when used as a LSP. And on CI, there is overhead from other things.

However, it remains to be seen to what degree that speed difference is due to ty's smaller feature footprint. It just doesn't seem to check the same things. I found it too permissive, personally.