If it is all client based someone could chose to use a patched version that e.g. donated all their money to charity. NB "never trust the client".

You will never get the big websites that monetise with advertising on board with client side analytics. That would need e.g. server side analytics or DRM on the client side app. Either way I wouldn't touch your app and nor would most that block adverts - and the big websites would probably not be that interested either.

Maybe with reproducible builds you could have a trusted build that people could build at home that also signed the requests with the analytics data. I don't think that the technology to do this exists yet.