Seems to me the most critical flaw is that you have to be online to receive funds, unless the sender is directly connected to you instead of hopping through intermediaries. This is inherent to the way the whole idea works[1].

Your only options are to either keep a lightning node online yourself, or to trust another node to custody your funds. At scale I think most people would do the latter, which sorta breaks the whole point of "p2p digital cash."

[1] https://github.com/moneybutton/yours-channels/blob/master/do...