It would be a lot of fun to play your double agent. It's not every day that you get to backstab the rest of your party! And now that I'm thinking about it, I'd make such a great boss encounter, with all of my hitpoints and fast healing.
But I'm already getting most of that just out of being under your spell. You're probably going to make me spy on the others whether I want to or not, right, and feed them false information or lure them into a trap? And I'll probably have to fight them anyway when they realize my duplicity and/or notice that I'm under a magic compulsion. I can have my cake and eat it too.
And I'd rather be on their side than yours, in the final showdown. It'd be a cool character arc for me, and the bad guys never do win, in the end.