(have mentioned this before - can't find the post)
Here it is:
Is it time to think about decimal precision ?At present, that means losing out on fractions of a cent, but in the hypothetical situation above, you could lose up to $10 on closing a channel.
I'd say the Bitcoin transaction fees are much more worrying: As long as the minimum on-chain fee is 1 sat/byte, and users often pay much more than that, I don't worry about fractions of a satoshi. I expect high fees to become a problem long before 1 satoshi becomes too large to be the smallest unit.