I think this (keyboard) case discussion is becoming a little sterile as everyone looks at it from their point of view and many just disregard that other have different uses of their devices and different life situations, and that's therefore just a matter of priorities, as I have said earlier.
I for instance use a silicon case on my phone, because I happen to drop it periodically from my pocket.
Instead I use my tablets naked at home as I don't drop them, I have no kids and pets at home, I find the grip perfectly fine and I want to enjoy fully the comfort of the device when I use them in my hands to read of to watch something.
I use the mini in bed, and it's fine for reading an ebook, but way too small for reading a Word or PDF document.
When I use my iPads on the go I use an Apple case (smart folio, smart keyboard or magic keyboard) as they are the lightest on the market but I have a laptop pocket on my backpacks so they are protected. If I ever bring them in a more "dangerous" environment (like a park, beach etc) I'll use extra protection, including the combo touch.
But for some people those more protective cases make more sense as:
- they are on the go all the time with their devices (I use a 2lbs laptop on the go most of the time)
- they have kids or pets at home
- they use the device on a stand most of the time and don't use it for reading etc.
- the worry that they could drop them would kill the pleasure of using the device
- they simply tend to drop their devices more often
- they want to put them in a normal backpack mixed with other stuff
- etc. etc. etc.
These are all valid reasons which change the priorities (and even just one of them is enough), and that's fine.... Just as wanting to enjoy the light weight at home is valid reason to prefer no case o just magnetic ones.