Wifi calling still routes the call through your carrier.

Or do you mean using voip services that operate independently of a carrier? The problem with those is that many services block voip numbers due to the rampant abuse by bots and scammers. As an example, I would not be able to sign up for my medical portal or any of my billing sevices as well as others(I tried to register with a voip number to protect the cell number I've used for decades).