Alice buys a car from a car dealer Bob.
She has yet to join LN so she opens a channel with Bob contributing a significant sum (price of the car), Bob doesn't contribute any funds to the channel. Entire channel balance immediately transferred to Bob with the first commitment transaction.
Alice plans to use this channel later to receive salary from her employer.
It would be far more efficient for Alice to simply make an on chain payment for the car, and then open up a direct channel with her employer. This would reduce the number of transactions that Alice would need to make in order for her to send and receive her payments.
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?