1) Consumption device People reading, scrolling, watching videos. Nice on the sofa, in bed, whatever. Also this use case has a lot of older users driven by eyesight issues that make a bigger slightly further screen interface better. Also very intuitive to young children (funny how often this elderly/youth overlap rears its head).
2) Creative (not productivity/coding!) device Artists needing pencil & touch interface for precise tactile writing/drawing/editing
You don’t think a non-artist, non-coder can be productive on an iPad?
Some jobs are heavily writing, reading, email/messaging, meetings, etc. Feel link those people can do quite well with an iPad, no?
My take is that consumers didn't want this; it was manufacturers trying to "add value" or sell something new. Same as the recent "AI PC" craze.