And as for rounding in mathematical way, that wouldn't be a problem for neural network, since it is a large distance from 1.4999... and 1.5000... from neural network's perspective, just like it is for you.
In practice, if we needed such a network, we would probably have a restricted domain, so there is only a finite number of discontinuous, and there would be a sufficiently large network that could solve it to an arbitrary precision.
We would not be able to do this with more exotic functions that are densly discontinues, such as the function:
f(x) = 0 iff x is rational
f(x) = 1 iff x is irrational
There is no way a neural network can reasonably model that function.And they are quite important to get right.
It's tedious, and wrong.
You aren't just getting downvotes from people who disagree with you (if that's why you're getting downvotes); you are failing to gain upvotes from anyone who either agrees with you or thinks your downvotes are unfair.
People downvote to disagree - and there's nothing in any site faqs or guidelines to say this is wrong - but those votes are balanced by people upvoting unfairly downvoted posts.