Depends on how much you rely on it. If your contacts can’t phone or otherwise contact you for your new address, they’re gone.
If the services you use don’t mail you OTP codes on every log in, you can still log in using your old email and update it.
You can also contact customer support of some services and have them change it, using other ways to autheticate, e.g. physical letters with generated OTP codes.
Yeah, but rules that allow bribing etc…