On the one hand, I would be very surprised if this sort of dashboard metric didn't already exist in some enterprise software somewhere. My management at a previous company literally asked me if we could do a daily report on who sent and received the most email in our department.

I refused to do it because I didn't like where I saw it going, but another coworker did. Unsurprisingly, the person who got the most email and sent the most email was the Sysadmin whose email account was set as sender for all the automated emails from the various servers, as he would literally email himself hundreds of alert emails a day, on top of all the crap newsletters and digests he subscribed to.

On the other hand, all of your coworkers asking you to not do something that could potentially impact their jobs, and you do it anyway as a hobby project? Sounds like kind of a jerk move.