The Mac Mini is a desktop computer, it's just much smaller than your typical desktop tower. It doesn't have a screen or keyboard built-in. It's not a laptop. It's a box you connect your screen to. How is this relevant?
The comment I was responding to was talking about screen size and only screen size. Your points may all be true (except that it has much more space for cooling than a laptop, which has significant effects on noise and sustained performance) but have no relation to the topic at hand.
It would be weird if the person you’re responding to were referring to personal efficiency—that depends on the person. They were likely referring to power efficiency.
I have 2 laptops, bought them to my kids for this times when online school is a must. I tried to do some work, didn't like the small screen.