They can't be. Not without an enormous amount of effort and risk.

Something I've been saying for years is: its inevitable that Bitcoin banks emerge. There's no other way it can work. It's just a matter of how good is the bank.

And as you point out the ordinary user is going to have a terrible time trying to manage something as complex as a lightning node or for that matter a. Ecash mint or any other way to move Bitcoin off chain.

Interestingly, in my view, lightning is not a service provider(bank), but a protocol. If you run your own node, you are being basically your own service provider, your own bank. And early on, that's what we thought lightning was going to be. But what it really has become is a communications protocol between larger entities.