Ignoring the iPad specifically for a moment, there are circumstances when a tablet is actually more appropriate than a laptop/notebook.
A few years ago, a friend of mine had a job inspecting buildings to see whether they complied with building codes. She carried around a tablet, not a notebook, because when you’re wandering around a building, it’s easy to check something off with a stylus or touchscreen while you carry the device, but a pain to have to stop, look for a place to set down a notebook, open it up, and then find the right spot with the touchpad or keyboard.
More recently, I read an article by someone who spent a business trip sick in bed, and found that it was a lot easier to use his new iPad in bed than to cross the room and sit at the desk to use his laptop.
Yeah, the iPad has problems (foremost, IMO, the fact that Apple has veto power over what you can and can’t install on it — which is part of why I own an Android phone and not an iPhone), but let’s not get caught up in the “I don’t have a use for it, therefore nobody does” mentality.