You're absolutely right. It's not Bitcoin. Neither is any other custodial Bitcoin, whether an ETF or a custodial Lightning wallet. None of it is actual Bitcoin.
That said, most people simply will not be willing to do what is needed for self-custody Lightning. I say that as someone who runs my own lightning node, and who has called out these LIghtning/Liquid hybrid wallets as not actually being self-custidy.
I am not sure it is possible to make self-custody approachable enough that most people will hold their own keys for anything outside of long-term savings on chain.