I tried out Fi when right when it came out, was pretty happy with it. fell on hard times, homeless here and there, so i paused my account because I was broke. I was able to unpause/repause my account every 6 months for a couple years and keep my phone number without paying a dime. It's a small thing, but I'm still pretty grateful I was able to keep my phone number for free like that.
It is probably something they already had internally that they figured they could monetize easily. They develop Android and RCS. Operating their own MVNO could very well allow them to simplify some things.
> many customer support issues.
Huh? I've used them for years. Never had issues which were not directly related to T-Mobile's network. There were no issues the few times I interacted with support.