What % of transactions really need to be instant AND have a trust model that is incompatible with the recepient accepting 0conf transactions?
There is definitely a use case for LN, not doubting it.
Discussion
Well, you said "We don't even need lighting" which the kind of the opposite of "There is definitely a use case for LN"
Any kind of retail that needs to move people through a line need an instant tranfer of some sort, even if it's not lighting specifically. If you want btc to be a currency, and not just a store of value, you need something that can do that. With 0conf you might as well be accepting a check, you'll just know quicker you got robbed.
And if you're coffee shop doing a 1000 transactions a day the utx0s are gonna be absolutely ridiculous.
That was bait