That's how T-Mobile does it - unlike other companies, once you pay off the phone your bill goes down.

It's literally a monthly payment plan for a phone, and they lock it until you pay it in full.

I see nothing bad about this at all. It's not like in the past where they lock your phone forever - with T-Mobile as soon as you fully pay for it they unlock it.

Imagine if your car dealer could restrict which roads you could drive on until you paid it off. Or if Best Buy restricted your internet usage to a limited number of websites until you paid it off.