Electrum's seed convention has nothing to do with the seed phrase of your hardware wallet. Electrum only has access to the master public key from the hardware wallet, so the the seed phrase never comes into play. Even if Electrum ended support for Bip39 seeds, compatibility with hardware wallets would remain unchanged.
I suspect that Electrum will continue to provide some level of support for Bip39 seeds in one way or another. Even if it's just a way to "sweep" a Bip39 HD wallet into a native Electrum HD wallet. There are so many hardware and desktop-client wallets out there that use Bip39 seeds and eventually many owner of those other wallets will want to import them into Electrum for one reason or another.
I've changed my HW seeds in the past, and it's damn convenient to be able to just import those seeds into an Electrum wallet. I just pack up that wallet and save it in an archive in case I need to access it quickly for some reason or another.
Good points.
For someone advanced like you a "sweep" is OK, but newer users will assume those coins are saved by the SEED used in the original Elec wallet. Then they don't maintain their old wallet and don't really have a good way to restore after a crash or failure of the HDD/SSD. I always recommend creating a new wallet to prevent LOSS due to newbie mistakes, but hey that's my take.
When I started this thread my question really centered around whether or not Elec SEED on a HW would add anything of value to security or industry improvements? Clearly Elec feels their SEED is much better. Is it, or is it hype? A mental exercise, yes!