We all know this by now right? We know computers store numbers in binary (unless using BCD) and numbers like 1/10 and 1/3 can only be approximated in a finite number of bits. This isn't news is it?
Also keep in mind that because computing is a growing field, the majority of people in it are relatively new to the field, plus there are plenty of people here that don’t have CS degrees.
FWIW, there are many representations for real & floating point numbers. Rationals are an example of something that’s neither floating point nor BCD, and can represent 1/10 and 1/3 exactly. Here’s a fun example: https://iquilezles.org/articles/floatingbar/
But I also don't think it is particularly 'news', the discussion on previous versions centered around the problems that arise from floats, such as inconsistent handling by tools and languages and 'inapropriate use' where the precision from floats is not good enough or misleading. So maybe it is more a "topic of interest".
1) it's really slow slow. Adding two fractions involves three integer multiplications and then running the GCD to simplify the fractions.
2) just simply comparing two rational numbers involves multiplication, which may overflow.
3) you can't represent irrational numbers. You can't do square roots, for example.
> numbers like 1/10 and 1/3 can only be approximated in a finite number of bits
Maybe I should have been more explicit.