Wait for text, image, etc on screen

So I use the control flow a decent amount. Mainly when it's a quick one off task and I can't be bothered to actually script it. But I've never really had a use-case for things like wait for text on screen or wait for image on screen. How exactly do they work. How do you guys use them?

for example if your action sequence launches an app or website, but takes some time and you only want to continue with the next action once something has become visible