Not even remotely true. It is entirely context dependent. I've always used floats when working in finance.
Some people say "goin der" instead of "going there", that doesn't change the definitions of words, just because people are lazy with their language.
Your point in the floating-point discussion is true, but you’re wrong about this one- linguistics is a descriptive field, not a prescriptive one.
I fail to see your point. Floats are best practice for many financial applications, where model error already eclipses floating point error and performance matters.