If execution of your binary is stopped some time between the call and return (with following restart), dealing with it is no simpler than dealing with network partitioning.
It is. Because then you know that the caller also must have failed. Whereas with an http call, you might want to retry, log the error, fall back to a cache, etc. etc.
This is ignoring the fundamentally-different issue that was raised, which is that the service boundary introduces a new failure point that doesn't exist in a function call. What you're describing could just as easily happen in a service call, IN ADDITION to the service just not being reachable.
It most certainly is easier to deal with the in-process version. I'm specifically referring to database transactions, which are much harder to have available in a distributed context. That failed network call complicates your life so much.
