Not sure if this even ranks on the "cool" scale, but I can say how LN was very useful for me this past week.

I had some small amount remaining of a shitcoin in my custodial wallet on LocalCoinSwap after doing a trade. (Don't judge ... when you need to obtain fiat and the only Buy offer for your payment method is in a shitcoin, then you acquire the shitcoin to then be able to sell the shitcoin.)

The remaining amount was a little under one dollar but I figured I could just swap it into bitcoin using something like FixedFloat. But that small amount was actually below Fixed Float's minimum swap amount.

So I first went the other way -- using LN I sent to Fixed Float about $1 worth of bitcoin for a swap that added to my balance of the shitcoin. Then when that deposit of the shitcoin confirmed I then was able to proceed with my original intent -- withdrawing the balance of my shitcoin (an amount nearly $2) to FixedFloat for a swap into bitcoin (delivered by Fixed Float, via LN).

It was more work than I would normally care to do for such a tiny bit of funds, but the satisfaction of eliminating even that small balance of a shitcoin provided to me satisfaction. And it proved further to me the utility of LN.

The ability to transact instantly, and pay just a trivially low fee ... is something incredibly useful.