LN has been vaporware for a long time, and it's always 18 months before it's ready. Recently the developers openly admitted they don't know how to scale it beyond 10000+ channels, because they don't know how to solve distributed routing.

https://www.reddit.com/r/btc/comments/719vis/lightning_dev_t...

https://medium.com/@jonaldfyookball/mathematical-proof-that-...

That is a very pessimistic view on the current state of LN. There are three independent open-source LN implementations [1, 2, 3] out there that are being worked on and already implement basic functionality. All three contribute to an document, called Basics Of The Lightning Network (BOLT) [4], which forms an open standard for LN.

I wouldn't call it vaporware. Yes, there are unsurprisingly open questions. But nothing which can't be solved.

1: https://github.com/lightningnetwork/lnd 2: https://github.com/ACINQ/eclair 3: https://github.com/ElementsProject/lightning 4: https://github.com/lightningnetwork/lightning-rfc

In the broad terms, how do you even imagine LN to work? Let's say I want to buy a $3 coffee at some random Starbucks I'm walking by. Do we have to first open and fund the channel? How much will it all cost just for that one off purchase?

Give particular figures please, no vague nonsense I hear all the time.

As for these implementations, I will believe it when I see it. You didn't even try to address the particular issue I mentioned.

You could be transacting your coffee with any crypto that Starbucks supports, and which is compatible with the lightning network. Litecoin will work for this example.

So Starbucks ask you to pay via Litecoin, which is fine by you even though you don't have a Litecoin balance. Atomic swaps over lightning network funded by some bitcoin you own, converted to Litecoin, is how you'll pay for your coffee.

What if they only accept bitcoin? That's the case for most businesses accepting cryptocurrencies.

Both of you are suspiciously avoiding a direct and simple question. How does LN work on Bitcoin in this case?

LN needed the transaction malleability fix in Segwit, so LN development stalled when Segwit was blocked for years.

Please tell us when LN will launch. Not some half-baked beta that chokes on 10000 channels, but the real thing.

Beyond what olegkikin mentions, the Lightning Network requires you to put stake (the total amount of bitcoin that can be used within those off-chain transactions). The illiquidity opportunity costs of that stake is greater than any value that the LN provides. There's a reason why we don't use pawn shops to buy groceries every week. Further, there isn't really a use case where you want to put some money at stake to do some transactions really quickly. Also, as Nakamoto† mentioned before, you can determine if a transaction is valid with very high probabilistic guarantee within a few seconds (with less risk than credit cards) without any change to the current network.

If for some reason you don't believe that, then there will always exist credit card companies that could provide instant transactions with guarantee as a middle man. Alternatively, there exists solutions like BitNotes.

†https://bitcointalk.org/index.php?topic=423.msg3819#msg3819