Both units naturally emerged from usage. There is no advantage in propagating other units, they only add confusion.
In addition there is absolutely no problem in expressing amounts below 0.01 BTC efficiently in Satoshi: You can just use the common abbreviation for thousands: 'k'.
So for example 100k Satoshi are 0.001 BTC. Simple and intuitive.
I agree with this. In a way, I feel like you can use mBTC/ bits/whatever if you want. Just stop trying to make it a standard. I want to say 0.00001 BTC. Why is that a problem? We aren't dealing with 5 year olds, any teenager+ knows what a decimal is.
Using lots of zeros isn't standard. While you can do it in general it is too error prone and inconvenient. World wide any teenager+ knows what mBTC or uBTC means, even if they don't know what BTC is. That is probably even true in the USA, so maybe it is time to learn the prefixes.
If you were to use decimals then it would be very clear as to exactly how much BTC would be in question.
mBTC - 1/1000th of a BTC
uBTC - 1/1,000,000 of a BTC
Even my 10 year old knows that. She doesn't have any clue or even care what a BTC is right now. She is only interested in money that she can cram in her pocket.