> Except for those third-parties, you mean?

The third-party can't steal your Bitcoins. Assuming your node is online 24/7, you can verifiably cash out your Bitcoin on the blockchain at any time.

The third-party doesn't hold your Bitcoin– both parties can close the channel and cash out, again without any trust.

Your Bitcoins can't be stolen by a third-party, unless you and your watchtower fail to broadcast a transaction with proof there was a channel transfer.

I read watchtowers are used to keep third-parties honest when nodes aren't online 24/7. https://blog.bitmex.com/lightning-network-part-4-all-adopt-t... They don't hold your keys.