Tablet computers are a type of computer with a touchscreen interface. They are essentially big phones. The main difference between a tablet and a phone is that the tablet is bigger. Most tablets also do less than phones. These features together make tablets somewhat impractical for usage outside the house or for any purpose other than reading. Of the tablets in the world, any that aren't being used as point-of-sale terminals in coffee shops and lunch spots are either permanently parked by a boomer's couch or collecting dust.
Because it is folly to attempt any serious computing of any kind on a tablet, tablets generally find application only to recreational purposes. If you want to read an electronic book, a tablet may be a fine and well-suited tool. If you want to make a program, you will probably prefer something with more power and a keyboard. Just about the only thing a tablet does better than a computer or a phone is facilitate drawing.
Meanwhile, tablets' size prevents them from being in most people's everyday carry. Phones do the same things, fit in pockets, and are easier to use with one hand.
All told, tablets are not dangerous, although they carry some risk of looking silly if you attempt to do something like take a picture in public using one.
