cesaref's comment is not good advice, it's not advice at all, it's a snarky take on how floating point is trickier than it looks
almost invariably floating-point calculations end up in some kind of comparison; if they didn't we'd probably do the calculations in a galois field or something instead
even equality comparison of floats is useful; there are an abundance of seminumerical algorithms which use it correctly on the results of computations. a trivial example is computing an attractive fixpoint by iterating a function and comparing each hare result to the previous iteration and to a tortoise. you have to be especially careful about x87 extended precision here
ieee-754 requires bit-exact results for the five fundamental operations
here is an example where your 'safe' generalization is not safe:
#include <stdio.h>
int main()
{
float f = 0.7;
printf(f == 0.7 ? "ok\n" : "wtf\n");
return 0;
}