1. All payments have to be routed across channels of arbitrary size across an arbitrary network. It's a small travelling salesman problem that only gets worse a

1. All payments have to be routed across channels of arbitrary size across an arbitrary network. It's a small travelling salesman problem that only gets worse as the network increases in size. 2. It requires a transaction to L1 to open/close a channel. If 1B+ people used it the Bitcoin network itself couldn't cope with that. At 7tps it can handle a max of 220M transactions per year. 3. You need enough liquidity in all channels to your destination to send a payment. This is fine for micro transactions but it can't handle $1k+ transactions well at all. 4. You have to re-balance channels or they stop working. 5. You need some sort of watchtower / guardian node to prevent the other person from being able to steal your funds. ZK-Rollups completely obsolete the lightning network. If Bitcoin did a hard fork to make them possible every single person would migrate to them. Lightning is not a long term solution, it's mostly a meme to throw back at people who say Bitcoin doesn't scale.