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by ParetoOptimal 1204 days ago
> Not in this context they don't.

What context is it exactly where they don't matter?

I can tell you in practice, in the real world, they very much do.

> They are useless if you want to ensure that a given number is a prime number.

It's not useless. The point is that once you have type `PrimeNumber` that can only be constructed after being validated, you then can write functions exist in a reality where only PrimeNumber exists.