Email confirmations should be standard but that's not what we're talking about here (and I'd expect that ~rsync is handling that properly).
Unsubscribing from transactional emails eventually causes the following support conversation: "Hi, uhh, rsync? Yeah, so, I'm having trouble logging in to my account and we really really need our backups, our intern just nuked a database. Yeah, it's uhh... cto@company.com. What do you mean my account's not active? ... ... Why didn't you just tell me my card expired? Well yeah, of course I unsubscribed, but I still wanted to know my account was being shut down!"
There's a scale of headaches happening here. At one end of the scale we have "nuisance", as in, "I'm getting too much email, or I have a stupid email address, or I don't know how to filter messages from reputable senders", and at the other end we have "job-ending cockup", as in, "I'm just now finding out that a critical part of our disaster recovery plan hasn't been working for a long time because somebody somewhere was inconvenienced by a notification, and I'm finding this out now because today happens to be the day we really need that disaster recovery plan".
Pushing the needle away from the nuisance end moves it closer to the disaster end.