My point is that it allows these kinds of things to happen. What's the point in making the number less accurate? In probability the difference between 0.999 vs 1.0 is enormous and these kinds of things can happen when you just floor numbers.
No-one I've seen arguing for fewer significant digits says that a probability of 0.999 should be rounded to 1. Nor do they say it's ok to round 0.5 to 0.