It also gives you a good foothold to realize whether the solution works or not into the future, a bit of a barebones formalism. You get to play with it in math terms before writing any code. This particular refactoring became the only thing in the codebase that didn't need to change as new requirements came along.
The key insight is you rarely need an exact number, just something in the right ballpark. And sometimes that ballpark is surprisingly big.
(More advanced sampling methods are basically just variance-reducing techniques which give you better precision at cost or lower cost for the same precision, but the big leap in ROI is learning to sample in the first place.)
A great tool in the toolbox to have while building software!