This is a good point were we adding it to base. It’s already in base and widely useful!
That’s a good motivation to add for fixing num and friends. But that’s not even a new problem for num instances in base. Reexport it from prelude doesn’t change that. Just improves the ergonomics for using a really nice type for both pedagogy and prototyping!
I also like how natural throws an error on underflow.
I'm going to play devil's advocate and say no. I believe Num instances should be rings under + and *. Natural is an instance of Num but is not a ring.