A display is a piece of hardware which can display content to the user; the content can now usually be an image, but there are displays which only showed text. They may be monochrome, although now they are almost all colour.
When it became possible to fabricate liquid crystal displays with many pixels in large arrays, for physical reasons they were the only viable display technology for use in lap-top personal computers, and that drove their development. LCD displays rapidly became the display of choice for all display applications, once they became economically competive.
Thus, when the invention of the blue LED permitted the creation of colour displays consisting of arrays of LEDs, those rapidly because the display technology of choice.