[marcosdumay]

As opposed to being responsible for maintaining and doing operational support of the service...

I still don't get what advantage exactly you are expecting.

Scaling it is only ever a problem for the service; you don't even have to think about it in a library. You can get telemetry from a library just as well as from a service; your users may find that a bit invasive, but it's still way less invasive than calling your service. And you can replace the internals of whatever, without having to worry about who will get affected, that's what defines internals.