The reason `overflow: scroll` is a better default is the need to account for every screen size or possible dynamic content. If overflow is set to `hidden` or wo

The reason `overflow: scroll` is a better default is the need to account for every screen size or possible dynamic content. If overflow is set to `hidden` or worse `visible` your UI is going to break on some screen sizes. So basically you need to decide if you want extra scroll bars for some screens, or broken UI when a user shrinks the browser. It's very time consuming to get everything right on every screen size on every browser on every OS.