Comments for utilizing "bits" denomination.
I propose that "bits" should be written in lowercase to differentiate as much as possible between BTC and bits.
Wallets and services do not immediately need to adopt "bits" as the default unit. Both "BTC" and "bits" could be displayed alongside each other in user interfaces for users to get accustomed to the new unit during a transitioning phase.
While I like the idea of a better denomination for 1/1000000 of a bitcoin, I feel it is confusing because there are millibits already (I believe the Electrum wallet uses them). Why not use microbits instead of bits? That way it corresponds to the standardized metric SI prefixes. So:
1 millibit = 1/1000 BTC, could also be written as mbit or mBTC
1 microbit = 1/1000000 BTC, could also be written as μbit or μBTC
[edit: sorry, missed the line about micro-bitcoin in the Rationale]
As a shorthand version of micro-bitcoin, "bits" could work, but may be confusing for newcomers, because it goes against the standardized SI prefixes. If Bitcoin goes to USD 1,000,000 then 1 bit would be $100 and 1 mBTC/mbit would be $100,000. To me that would be confusing.
Maybe we should not use bits/millibits/microbits in writing, and only use them in speech. Then the mBTC and μBTC could be made to be the official ways to write them?
I agree bits is not the best name and could lead to confusion given the existence of mBits which I have seen in various wallets. If you don’t like the way micro bits sounds why not come up with new name for them like microns. I think it would be pretty intuitive for people realize that you get a micron by shifting the decimal 3 more places from a milli bit.