- It forces everyone who wants to receive money to constantly run a node at all times. If their node goes down at any time (or is intentionally taken down by a hacker), in certain situations, they could lose money.
- The channel provider needs to lock up a massive amount of BTC to provide liquidity to channels for all users. It costs BTC to open the channels.
- It's brittle because you need many watchtower nodes to constantly monitor every single participant in real time in order to ensure that nobody cheats and rolls back valid transactions.
- Watchtowers could be fooled by attackers to spend all their processing time on fake frauds to distract them from real frauds.
And there are a lot more serious vulnerabilities outlined here: https://www.coindesk.com/bitcoin-lightning-network-vulnerabi...
I think for high volume payment processing, we might as well use centralized payment providers off-chain.
Such as...?