It's a bit of a catch 22, if you lose your iPhone then you need some way to locate it / erase it without having your iPhone. I don't think it's a big deal, you should have backups anyways.
One thing they could do is, if you have more than 1 device on your account, then force you to use another device for 2fa.
One thing they could do is, if you have more than 1 device on your account, then force you to use another device for 2fa.