Maybe Google doesn't want users blocking ads from getting loaded.

ADs work via play services so even if you block internet for the app the ADs will continue to work.

The reason many apps stop showing ADs when their internet is blocked is because they need to make an API call to their own servers before running the AD. That is the common behavior but not mandatory

Wait, we can in Android. In my OnePlus 12 in the app settings under "data usage" there are two toggles for "disable mobile data" / "disable wifi"

Not present with a Pixel with Android 16, my effective choices are:

1. App can't use mobile data in background

2. App can use mobile data in background except in Data Saver mode

3. App can use mobile data in background regardless of Data Saver mode

____

For anyone doing comparisons, the literal settings appear under "Mobile Data Usage" as:

* [X] Background Data ("Enable usage of mobile data in the background")

* [ ] Unrestricted mobile data usage ("Allow unrestricted mobile data access when Data Saver is on")

You mean Google-Android.

Wow, thought it was GrapheneOS only, but no.

Confirmed these settings on One+15 on OOS16 (based on Android 16).

Is it also the case for other Android brands?

P.S. I did use it before to turn off ads.

Google's Pixel phones (near stock Android) famously do NOT have the option.

Google is invested into you having WiFi all the time.

Weirdly, my very old Nexus 6P with the WiFi off, could lie untouched for weeks, with almost no battery depletion. Yet if I turn the WiFi on with near stock Android (meaning no messengers, tens of email accounts, etc, to constantly ping _something_), it just eats the battery within 24 hours tops. Perhaps that’s just the module itself, but I remember flashing LineageOS and having better savings. I have no real numbers to support that right now, although I still have the phone lying around somewhere and could test this some day.

Modern Google Android will use neighbouring WiFi networks to guesstimate your location quickly, so it's scanning even when the toggle says "off" unless you disable it. This location can be queried in the background when nearby devices broadcast the equivalent to Apple's "find my" network broadcasts, because Google uses collected reports of beacons+location to roughly locate tags and such. Opting out of all of that stuff should massively improve standby battery time.

I've also noticed the difference between vendor+custom ROM with a Xiaomi device, which I use as a second phone around the house for controlling smart lights and such. The biggest difference there seems to be that I don't have as many apps installed and as many features enabled, because during active use and shortly after, the battery drains just as fast as (actually a bit faster than) when using the original ROM.

Many custom ROMs (at least the LineageOS-based ones) also don't do thing like configure the country code for the WiFi chip and GPS caches. A large part of the 5GHz spectrum simply doesn't exist (by default) on my custom ROM devices so there's just less to scan in the background.

I believe this has been part of LineageOS since before it was called LineageOS. Most custom ROMs have some kind of internet filtering capability.

Some Chinese/Taiwanese brands do it too, but most western brands don't seem to include a firewall.

Xiaomi phones also have it but you can block Wi-Fi only for user (non system) apps. However you can block mobile data access to all apps.

None of the Samsungs I have owned so far had this feature and neither did my last Pixel.

I have an S25 Ultra with the latest version of Android, and these options don't seem to be there at all. I don't have a "data usage" under Permissions for any apps. I do have a Mobile Data section under App Info for any given app, but there's no way to toggle the options you mentioned.

You can on some devices (many Chinese brands, funnily enough) and on custom ROMs.

There are also (open source) firewall apps that will let you block (non-system) apps if you're on a stock ROM like me.

Technically, this is a permission, just not a user-grantable one. Google has moved quite a few permissions from inherent to user-grantable, but most apps don't work without internet (unfortunately) so I doubt they will do it for the internet permission in stock android.

It is a permission that app can get without asking the user