I need to state my philosophy about bullpens and relief pitchers right up front: relief pitchers are, objectively, the worst baseball players in uniform at any given point. Put it another way, the worst players on any baseball team can be found in the bullpen. Here is my one data point to validate this opinion: position players can be used to do their job.
So, from a human perspective, that’s pretty gross. Yes, it can be fun to put numbers into a spreadsheet, but those numbers, good or bad, are generated by discrete event generators known as baseball players, who are, exclusively, human beings.