Interesting. So it's like lots of little ledgers, each channel stays open until N number of transactions between two people complete, then the finally tally is pushed onchain when the channel closes. Am I wrong to thing this sounds a little risky? Like, that channel could be "lost" after the goods/services were exchanged, leaving the seller holding the bag. I don't understand what kind of recourse the seller has to LN if LN screws up? It's kinda like escrow, but escrow agents are heavily regulated whereas is LN "trustworthy"?
EDIT: ah, I think "nicpottier" explains a little more, below. about having an account on LN requires a certain amount of a deposit (like a debit account).
Each update to the channel is a new transaction that references the opening transaction, on each update, this transaction is replaced with a new one, so in practice only the last transaction is kept (old transactions become dangerous to publish)
The big difference is that bitcoin's scripting language is not turing complete. This is a security and scalability trade off that the bitcoin community isn't willing to compromise on, which drove people like Vitalik (started as a bitcoin dev) away to start Ethereum.
I haven't looked into this much, but there are projects like Rootstock, https://www.rsk.co/, that essentially recreate all of Ethereum's functionality as a bitcoin sidechain.
It has always had, it is just much limited than ethereum's.
But you can express things like "if X and Y cooperate they can spend this transaction or Y can spend after 1000 blocks or X can spend if it reveals the preimage of this hash ____"
These logics are what LN uses in its update-transactions
EDIT: ah, I think "nicpottier" explains a little more, below. about having an account on LN requires a certain amount of a deposit (like a debit account).