It really depends on who you mean by "That's what *we're* here for". You, me, and self custody maxis are probably a very small group of people. I don't know of any other person who uses their own lightning node for zapping other than myself and a small set of very technical people.
If we're talking about sending and receiving small amounts of nostr, I think a large portion of the population would be ok with custodians for those.
We're not talking about storing your life savings on nostr or custodial lightning nodes. onchain is always there when you want to do that.