2) Can run on commodity batteries -- AAs are cheap, user replaceable, and supplies are easily available worldwide
3) More rugged -- can be dropped without fear, no need for aftermarket cases/screen protectors
4) Keyboard included -- no need for aftermarket add-on, unlike most tablets
5) Cheap -- you can buy one for an order of magnitude less than the cost of a tablet, or even more less than the cost of a notebook
Which isn't to say devices like these are better for everyone than a tablet or a laptop would be, just that those devices don't automatically make these irrelevant for their niche.
2) Can run on commodity batteries -- AAs are cheap, user replaceable, and supplies are easily available worldwide
3) More rugged -- can be dropped without fear, no need for aftermarket cases/screen protectors
4) Keyboard included -- no need for aftermarket add-on, unlike most tablets
5) Cheap -- you can buy one for an order of magnitude less than the cost of a tablet, or even more less than the cost of a notebook
Which isn't to say devices like these are better for everyone than a tablet or a laptop would be, just that those devices don't automatically make these irrelevant for their niche.