My iPad mini gets multiple times more use than my iPhone, there have even been times where I’ve left my iPhone by the bedside table for days.
It’s mainly a consumption device, I got it initially for reading ebooks while on the train. It’s also a surprisingly good workhorse by itself, or as a second screen for a MacBook. I even make phone calls with it (via the iPhone) simply because it’s always in or near my hands.
So the Duo certainly piqued my interest when it was announced, until I learnt it doesn’t do iPad-y stuff like universal control or sidecar. I’ll wait for the next gen.