In Defense of Polyfills

Standardized APIs have intrinsic value, independently of browser implementations.

We think of polyfills as a toggle: use a polyfill, leave it in there, and later when all browsers implement the feature natively, it gets removed.

This misses out on one of the biggest benefits of polyfills: decoupling API design from implementation.

Completely agree. It's nice when you can easily enhance functionality while not tying yourself to a specific implementation too tightly. Time moves on, implementations become standard across the different browsers, and you can go in and get rid of code. It's a great feeling.

It can also help handle things if a library ceases being maintained, or a vulnerability of some form is found in the polyfill library, or anything else. The easier things are to swap out implementations in general, the better.