A very good point from lajackson... Don't make the assumption that all your emails are exactly the same even though they look like it at first glace. I usually get at least 2, (maybe 3 sometimes, I can't be sure because I don't have any recent examples. I can't seem to convince my ward to really use the calendar so we don't get a lot of events added)
If you look at the bottom of the email there is a bunch of disclaimer stuff stating who you got it from and why, along with links to unsubscribe, etc. That information may be slightly different stating that you received it because you subscribed or that you received it because you are an administrator, etc.
Personally, as an administrator I used to like getting both because it showed me what other subscribers were getting as well as giving me the one specific to my calling. That said, it isn't what it used to be... On the classic ward website I had to approve every calendar entry, so I wanted notifications that there was an item waiting to be approved. On the new Calendar pages, that is no longer a necessity and I can see how sending additional emails to administrators may not be necessary any more. Perhaps they should only be going to building schedulers and not administrators. A suggestion at least to consider for the developers...