Quote from: stdset on March 31, 2017, 04:13:31 AM

My scenario, onchain txses: channel opening.
Your scenario, onchain txses: car purchase, channel opening.
Possible drawbacks in my scenario:
1) Alice can't pay for anything with the new channel before she receives the first (after the purchase) salary.
2) If Bob doesn't offer intermediary services or if he charges incompetitive fee for conducting payments, it's better to open a channel not with Bob, but with a competitive hub and route the payment to Bob through the hub. If Bob's channel capacity with the network isn't enough, he can open another channel with a hub.
So, what do you mean?

Over the long term, there will be more on chain transactions and more costs with your scenario.

In the US, the average car is ~$25,000 and the median household income is ~$50,000 per year.

Under your scenario:
Alice opens the channel with the Car dealership (1 on chain tx). In order for her employer to pay Alice through the car dealer, they would need to have a payment channel with more than $50,000 to pay Alice for the year (which I find unlikely), or they will need to load their payment channel to match Alice's salary (another on chain tx). Now in order for Alice to receive her entire $50,000 salary, she (or the car dealer) will need to close a payment channel (another on chain tx), load up Alice's channel (another on chain tx), and probably open up another channel with whoever they closed with (another on chain tx) In one year, Alice will have made or required to be made 5 on chain txs. Furthermore, the car dealer is likely to charge a fee for being a third party between Alice and the employer.

Under my scenario:
Alice sends 1 on chain transaction for the car. She opens a payment channel with her employer, who loads into the channel however much they expect to pay her that year, so $50,000 (another on chain transaction). At the end of the year, the channel is loaded with her next year's salary (another on chain transaction). In total, she makes only 3 on chain transactions, and does not need to pay a third party for being a hub. Like with the Car dealer, Alice can buy things by using her employer as a hub, but because the channel already has her entire yearly salary there, no on chain txs need to be made to load any more money into that channel (unless she is spending from here savings).

Lightning is fairly useless for big one time purchases. It is far more efficient to use just a normal on chain transaction to make a big purchase like a car or a house.

A far more likely scenario for one party to put in 0 funds into a channel is for an employer to be paying an employee.