I'm sure it works just fine as long as nothing goes wrong. However, it's good security practice in any context to test execute a full recovery process to ensure it will work when you need it to (e.g. if your Bitkey device stops working). Obviously, I can't speak to whether you have personally done so; but, I imagine it's not practical at all for most to simulate acquiring a new Bitkey device (by factory resetting the one you have), have Bitkey generate new keys for the new device; and move funds to the new keys on your behalf (at a Bitcoin network fee cost to you, the user)... and even then, this potential scenario creates an inherent reliance on Bitkey servers to be there for you when you need them to be (i.e. this part of the recovery process is out of your control).