that's why bit = 1BTC because otherwise names like microbit would not make sense. A centimeter is not the same as a meter, so a bit is not the same as a microbit either.

People will use microbit/millibit because that's just the natural thing to say instead of microbitcoin and millibitcoin. If you have never heard of any of the names the community has thought of, these are the first things that most people will think of. And since we are still in the innovators / early adopter stages there will be many new persons joining every day for the next couple of years. If we would use 'bit' to mean anything else than a full bitcoin, i can guarantee you we will have this very same discussion for years to come.

If you are not looking forward to keep explaining that for some reason a bit is somehow equal to µBTC for the next couple of years, just tell them 1 bit is an abbreviation of 1 bitcoin and be done with it.