safe-area-insert is useful to provide some padding to avoid cameras and virtual buttons. This is not needed because the browser handles it for you already.

It's still needed for elements with position: absolute or position: fixed

Browsers by default will prevent your site from being obscured by the notch or home indicator, so your content will be safe without any special handling.

Ideally we want the content to stretch edge-to-edge, but we want to make sure they're not obscured by system UI. To get that, you need to opt in to the full viewport and handle safe areas yourself.