Dunno if you want a serious answer, but 'press start' titlescreens that start up an animation if you leave it unpressed too long are a throwback to when if a screen showed the same image for too long, it would fry the image on to the screen and leave a little ghost image, so screensavers were a screen saver. This allowed one to demo software and just leave it running without worrying about damaging the product hardware.
These days however it is totally unnecessary.