Private keys are the same, BIP39 and Electrum, and also pretty much any other wallets will generate private keys of the same format, ECDSA private and public key pairs are the same for Bitcoin's curve. WIF is adopted by most if not all wallets as well.
The key difference lies with the limitations of BIP39 seeds, reliance on wordlist for checksum is not ideal, lacking versioning and contributing to any user's confusion, and as BlackHatCoiner mentioned, better checksum by lowering risks of false positive. I don't think there is any argument to be made here, you can refer to Electrum's docs on their seed system and you'll realised that it doesn't lack anything that BIP39 has but improves on many of the shortcomings