You could've just made a regular seed with electrum and use a BIP39/BIP44 derivation path though?
No, he couldn't. That's the whole point of this thread. Electrum seed mnemonics are NOT BIP39 compatible. If you try and put an Electrum seed menmonic into a BIP39 wallet, it will tell you that it is invalid and/or that the checksum has failed.
The algorithm for creating the mnemonic from the same "seed" (ie. the big random number) is different... so even if you start with the same "seed", Electrum will generate a different mnemonic to a BIP39 wallet.