I don't see any difference. 
The thing I highlight is they said "Current tax rules make buying a coffee a taxable event" there's nothing different if the customer pay using on chain, lightning network, L2 or any other network, it's still a taxable event.
The improvement that I see merchants don't have to set up or spend more time to accept Bitcoin payment, because Square already sell the hardware which is ready to use.
The thing I highlight is they said "Current tax rules make buying a coffee a taxable event" there's nothing different if the customer pay using on chain, lightning network, L2 or any other network, it's still a taxable event.
The improvement that I see merchants don't have to set up or spend more time to accept Bitcoin payment, because Square already sell the hardware which is ready to use.