[__jonas]

Very annoyingly, the iPhone also has a way for the carrier to somehow disable the mobile hotspot feature of the phone for their sim.

On the mobile hotspot settings page it will just show a message with a link to the carriers website instead of the toggle to enable it, I find it really annoying since as you said I don't understand how there would be a difference in what the usage would look like to the carrier and it feels like Apple is imposing a restriction just for the benefit of the carrier that makes the phone less usable.

[sneak]

This is Apple's fault. Android phones do not have this problem.

[SkyPuncher]

Android phones have the exact same issue. For years I had to use an ADB work around to get tethering.

[inemesitaffia]

Android does

[herbst]

Not sure if android has that but I never heard of anything like that here in Europe.