At a certain point it'll hamper ability to ship features quickly, as you go from having to think about the 80% of uses cases, to spending a significant chunk of time anticipating and fixing all kinds of very unlikely edge cases.

I guess it's preference, but I'd rather ship quickly and cover most of my users, and respond to any bugs that do surface (and there's every chance they won't) for obscure issues that probably won't really impact revenue.