Binary can be any number you want if it can be written as a fraction of two to the power of n. So, no, not just 0 and 1. That would be a binary digit. Yes, technically it can't have decimals, but can have digits after the radix point, ex 101.110 = 5.75 . Some can't be translated like 1/3 can't be written in base ten, 1/5 can't be written in base two.
So we should all go out correct people that argue against a binary gender classification that what they really mean is that gender is not single digit binary, or single bit, or that they should use words and expression they know the meaning of like "either/or".
I think this plan will go over really well.