Physical attraction level: I guess it's high enough to have him here in the final three, but I'm not particularly sure why.
The ways Chase might've blown it: By telling JoJo he loved her. Didn't think that would be what did him in, did you?? As soon as he told her, JoJo's face turned into a petrified mask of dread, she ran away to a bench outside the hotel room, leaving Chase to pound wine, and then came back and told him he's gone.
I've said it before, but it bears repeating: JoJo is the best Bachelorette at cutting people that I have ever seen, by far. She tells the guys exactly what's going on in her head -- in this case, that she didn't feel the way that she thought she would when he told her he loved her, and that she wouldn't be ready to tell him she loves him in a week -- even if it hurts like hell. She's fair, she's honest, she's rarely boring or mechanical, and while she doesn't sugarcoat any of the message she needs to deliver, she's also not unnecessarily brutal.
She lingers a bit too long on the Chase-cut (maybe I should've saved that sweet pun for here??), because she clearly wants everyone to like her, even those people whose hearts she's just run through a paper shredder. But ultimately she does what she needs to do, and doesn't think that having sex with Chase this particular evening will solve much, likely because he's similarly boring between the hotel sheets they only wash every three days.