The problem is that connexions is awful. Frequently, I find prices higher on the portal than direct. Also, they can only book into basic economy. With basic economy moving fleet wide to AA in September, this is a problem for me because I'm PHX based. No status mileage accrual, middle seats, no carry on. No thanks. I would pay the $20 up charge for regular economy, but connexions acts like you're speaking Russian after a 40 minute hold. Irrops or schedule changes? Forget it. They are useless.
Also, the thing where they don't transmit your booking to hotels until a few days before the stay is stupid. Not usually a big deal, but if you want to ask for connecting rooms or whatever, the hotel has never heard of you.
Connexions seriously diminishes the value of 1.5 to me and is probably the reason I will be just fine with CSP when my annual fee comes due on CSR.