But I was saying it strengthens it? One leaf exposes A,B. One exposes A,C. And one exposes B,C. So onchain you only see the 2 that signed, not the 3rd. Pretaproot you see all 3, in every signing event.
But now I've written that out, it only helps in terms of blockchain publishing I think. If you literally own 2 of 3 devices, you clearly will be able to see all 3 pubkeys.
