From what I can tell, internet access is the default just to allow apps to have advertising. Too cynical?
Android originally could deny internet access to Apps which I found useful.
Certainly I don't want an extension or plugin to have pull access to the internet. That may limit functionality. But often only push is needed (e.g. blocking list could be pushed). No third-party keyboard should have internet access.
Edit: rewrote a little clearer.
I spent a bunch of time trying to figure out how I would implement such a feature on a standard Linux system to sandbox apps on my PinePhone, but there's no sane way you can implement a standard "you can have internet access but not touch my local network" policy.
Of course, if you've bought hardware controlled by it, that's unfeasible. Keep it in mind for next time.
I don't suppose there are review sites that mention how predatory and nagging a mobile app is?
I've basically given up on mobile apps around when the ipad 3 was launched and never looked back. The reasoning being that i got an ipad 1 when it was new, and you could still find pay once games then. But they all got replaced by free to play gambling applications mislabeled as 'games'. Then the news about utility applications tricking you into $50/month subscriptions came about...