With cookie banners, legislation said that every website needed to ask for consent -- a thousand sites, a thousand banners.

Operating system level controls, though, provide a single control plane. One can very easily imagine OS-level toggles per application of:

[No Internet, No Internet outside your own app-sandbox, Ask me every time, Everything is allowed].

No opt in from apps required -- they might break if the network is disabled, but the user is still in control of their data.