When hunting down a function you want to deprecate/remove in your private imperative language codebase, you can probably find all call sites just by grepping —

When hunting down a function you want to deprecate/remove in your private imperative language codebase, you can probably find all call sites just by grepping — and even if you miss some, in most cases you'll get a hard error of some kind (either compile time or runtime) after removal. But with the cascade, call sites are implicit — and removal, for better and worse, doesn't cause a hard error. All it takes is a single rogue engineer or product manager to mess things up. And then cleaning things up later is difficult because of all the places that have to be inspected.