Tmobile Magenta Plan Vs Xfinity Mobile Select/Mobile Plus

Um so right now I'm going to be paying 148 (74$ each) for two lines a month on the phone on the old grandfathered tmobile magenta plan.

I've just come to learn that xfinity offers a plan for 35$/45$ if you have internet with them already (which I do). I've come to learn that the xfinity plan also has unlimited talk/text/data for when you are traveling internationally.

I was not aware of this. Is there any reason I shouldn't be switching to xfinity for my phone plan considering it's basically half the price!?