There are two types of displays when it comes to TVs and monitors. The first, older type is the CRT display, which stands or cathode ray tube. These are very wide from front to back and are very heavy. They also have glass screens. LCD displays on the other hand are lighter and thinner. As a bonus, they consume less energy, though, they are easy to scratch because their screens are more sensitive to touch.
I think that if a teacher knows that the computer will not be moved and they small children will be working with it, they might want to go with the CRT display. If the computer needs to be more mobile and is used by older children, a teacher might want to go with an LCD display.