Which systems enforce Secure Boot out of the box and lose functionality without it? You mention something ASUS and Intel graphics being broken without UEFI which isn't the same thing.
It does. Except they call it verified boot. Maybe rooting was the wrong term, it’s more about installing custom ROM, where this mechanism prevent your custom ROM from getting hold of DRM keys.
Which systems enforce Secure Boot out of the box and lose functionality without it? You mention something ASUS and Intel graphics being broken without UEFI which isn't the same thing.