One of the most meaningful differences for a productivity perspective is monitor support. I went with the studio simply for that, since the prices were so similar.
You mention 3 vs 5 but its not that simple. High refresh high resolution monitor support differs greatly between the two. But then there is portability. The studio is heavier and larger. The more they weigh, the harder they fall, as they say. If you're going to be traveling with it a bunch, the mini will be easier to protect, with more effective cushioning. Effortlessly fitting into all kinds of spaces without weighing you down.
I don't plan on traveling with it, it sits in my office. I'm not pushing the limit on an m2 pro's monitor support, not even close, but why go with the mini for the same price, with less cpu and gpu cores? Just doesn't make sense for me. If I was going to travel with it a bunch though, I'd definitely go with the mini.