you are missing the complete point
I'm not, we're speaking about the same thing.people wont know of the rate change while using LN.. they see the msats and dilly dally happily moving msats in onion payments
.until.. they broadcast the commitment and see onchain that they are getting not as much as promised.. [emphasis mine]
then you will see
I acknowledged that you can indeed lose 1sat. So yes, you're wrong with the bolded sentence; they may get up to 1 satoshi less than the msat amount in their wallet..until.. they broadcast the commitment and see onchain that they are getting not as much as promised.. [emphasis mine]
then you will see
Although, this is nothing new and nothing to worry about; 1sat is worth $0.00016USD or 0.016 cents.
converting a onion payment amount of 99,999msat
to 10sat is not a rounding error
its a full conversion at a 1000x rate
that 1000x rate is the part im on about not the idio roundong silly petty brush under carpet arguments you think that only happens in LN
Do you have an idea about an off-chain system which doesn't need to be 'watched' / online? That would be amazing. 
yea. its called bitcoin
i dont need to be online all day to "watch" it for theft. heck it even comes in the form of paper wallet
when anyone wants to make a internet payment then yes go online. but the rest of the day-month-year, you dont need to stay online just to ensure a partner/middle man isnt trying to steal against you
its crap like LN that is the only system in cryptocurrency that so you need to be online to reduce the risk of someone stealing your funds.
. in bitcoin i can disapear for a decade and come back and know my finds are safe.. LN channel cant say the same
i dont think you LN folk realise that LN "tech" is actually the failed projects of cypherpunks 2000-2007.. it was then bitcoin and blockchains that solved a problem for smart contracts..
its not where smart contracts are solving a problem of bitcoin.