The numerical salary shouldn't be the deciding factor. I want to know if you're interested in the work that you'll be doing and the team you'll be working with. I don't want you to think, "man I wasn't going to go there but they offered a huge salary!".
Of course the salary is relevant, but I want to know that we're just negotiating on the number, and not number+job.
Are you interested in the work that we'll be doing? Yes? Good, is this number high enough to make it worth your while? No? Ok, well that was the highest I could go, so thanks for your time.