Here's a simple example (which I just made up) followed by a very complex example.
In this simple example this code will launch the game Mini Motorways, then wait until the splash screens are all finished, which is "determined" when the screen contains a large "PLAY" button, which looks like the following. Notice that the words in this game are in GIANT fonts and can appear in any colours or brightness, and my code will still work. This is so much better than searching for images on the screen. You could try to use Find Image but that would be much more complex, and it's very doubtful that AppleScript (or Press Button) would work at all, but OCR is amazing for this task.
Now for the complex example. Here's a macro, below, that uses a form of recursion combined with OCR to find the location of a word on the screen: (it's normally not possible to find the location of a word in the screen, especially if the word can be in different sizes or colours)