I just learned that I've been using a wallet (SBW) where the hosted channel I'm using is pretty much running on autopilot, as the owner of the node is serving his country against the Russian invasion. And even knowing that, I've still used it.
With that wallet, I keep maybe a max of $25 worth of bitcoin -- for things where I want to pay from my mobile that I carry with me. I've never used LN for a P2P trade, but as RoboSats grows, I could see where that opportunity may come, and thus I would probably decide to go with some other option -- maybe even a custodial one but it swould only be one that I feel can be trusted, due to the higher amount (e.g., Wallet Of Satoshi).
Of course, I can run my own LN node -- but as you mention, there i more "under the hood" to be able to do that. For example, if I want to use this for a $200 trade, I need to have $200 worth of inbound liquidity (if buying bitcoin), or $200 of outbound (if selling).
So you are right. An account with LN support (like your account here on SN), or an account with an LN bank (e.g., Wallet of Satoshi), or a wallet with LN support where using a hosted channel is a choice available (such as with SBW or BlueWallet) -- these all provide convenience and it is likely how the vast majority of people who use Lightning will operate. Does that mean millions of people are using a few of these banks (e.g., Wallet of Satoshi, CoinOS, etc)?
Not necessarily. Maybe the open source Bitcoin Beach wallet, which uses a multisig shared custody model, will become more widely implemented. Maybe down to family groups even.
Nicolas Burtey (Galoy) on the shared custody model of Bitcoin Beach Wallet
So essentially, we have numerous choices. If you want financial privacy and to control the keys, run your own LN Node, there's no alternative. If you want convenience only, use a custodial account (e.g., Wallet Of Satoshi). Want some where you aren't using an account on a third party service, nor a bank like Wallet of Satoshi, but something in the middle, find (or form) a tribe you trust that has implemented Bitcoin Beach's multisig shared custody.
And it's not like you are storing your life's savings on LN. Your LN wallet is primarily for transactions, not for use to store significant amounts of value.