Its a spectrum, even when electrum created the concept of what we call today a "light wallet" there was problem regarding not validating yourself the transactions and delegate to a third party. But light wallet are an immense scalability solution and a tradeoff that can be useful in most cases. Nothing is really black and white, and I think that good hybrid solution are what we realistically need to scale. Ecash for little payments I think is really a cool tradeoff, I dont care to have a 100% security to not loose 50 bucks and delegate custodial. Privacy is more important for this kind of use, and with cashu you have it.
Is like entering the cinema and pay the ticket 1 hour prior. Nothing assure you to not being rugged, you have an abstract custodial asset redeemable at cinema entrance. I dont see no problem with having a custodial cinema ticket if I decided I'll want to see a film today.