Out of every time Paige uses magic annoyingly, I don't feel this time was personal gain (or last time technically). Her promotion wasn't the intended outcome of the spell. To me personal gain is when you cast a spell to get rich, cast a spell for yourself with a desired outcome. When she fixed Carolyn's face, the outcome was for her to get her child back and to be able to appear in court, nothing more. So I feel it wasn't personal gain and she should've been able to accept the promotion.
I found Phoebe's spell a bit on the side of personal gain but at the same time it wasn't I suppose. I don't feel that Phoebe was questioning whether she should marry Cole though, to me if you question the groom then there's a problem. I feel she was questioning the idea of marriage, questioning what she will be like as a bride etc etc but not if Cole is the right groom. At least when she cast it. Maybe cynical Phoebe made her question Cole as well but I don't think it was her initial intention (even if that's what she wrote, I don't believe it's literally what she felt).
One thing I want to wonder is why Cole simply doesn't tell Phoebe, I think the sources powers are inside of me, we should make another power stripping potion.. I mean I get why the writers didn't, but you have to wonder why he wouldn't just do that.
I didn't really like how suspicious they were over Cole 'getting the knife from Kurzon'. I mean it's not the first time demons chose hand to hand. The Source stabbed Cole in the premier because he wanted him to suffer, the two Belthazars battled hand to hand opposed to using energy balls, so I think it's reasonable to assume he went after Cole with a knife, and if that's the case, Cole is very experienced in hand to hand combat and could've easily gotten the knife away. But no, they all just seemed to automatically think "omg evil!"