The most common reason I’ve heard is that devs want to be able to use cutting edge features and the update cycle for OS bundled browsers is too slow to accommod

The most common reason I’ve heard is that devs want to be able to use cutting edge features and the update cycle for OS bundled browsers is too slow to accommodate that. I find this argument a bit silly, because there are few applications that actually need said cutting edge features and even if you’re one of the handful there’s always polyfills, but maybe I’m missing something.