Alby is more recognizable, "sign in with extension" adds mental friction.
The code is the same, it is just https://github.com/nostr-protocol/nips/blob/master/07.md
In fact it also works with nos2x whitout any problem.
It is just a bad communication/UI/UX, easy to fix
Discussion
This is a false solution that reduces accessibility/usability for everyone that don't know what Alby is, and also promotes single vendor, in my opinion.
Just remove the danger "login with nsec", create a unique "Login with Nostr extension" and below explain what this extension is, why it is important and how to choose/install it.