I mean, yeah, Beau was bad, but he was like overtly bad. The "I'll fuck you up in this way if you don't do X" kind of bad. The devil is just... We don't know. He keeps offering deals that are too good to be true and expecting seemingly nothing in return, which—because inhuman things—makes him loop right back to really really bad, but we don't get to know why.

The unknown factor, the feeling that Ashley's surrounded in a net she can't see, is what I think puts the devil above Beau here in terms of "This guy is bad news".