I think I should clarify my question.

If the lowest unit of measurement for bitcoin is a satoshi.

How do you chop up a satsohi even more?

Is it 1000 milisat = 1 sat?

Will we reach a point that bitcoin becomes so scarce that 1 millisat becomes the new sat?

Are we capable of sending 1 millisat right now, or will that be possible in the future?

How do the channel fees work using millisats?