Things like this are never considered "security practice" if you ask me. They are false sense of security.
Exactly. It's like generating a random 32-bit number, passing it through SHA256 (maybe bunch of times) and consider the result's security 256-bit. It's false sense of security of someone can end up to your number by another way than generating it randomly through a 2
256 range.
I hope you have skill and time to write custom brute-force software (or fork and modify existing software) which check generated seed/address on different PBKDF2 iteration number.
That is also a drawback. If you pass away (knock on wood!) your family won't be able to recover your funds somehow unless you've hidden it in your hard drives. I hope you acknowledge how impractical it may get for no reason.