So you know how when you watch a movie on a Blu-ray disc, you have to put the disc in a special machine called a Blu-ray player, right? Well, a Blu-ray ripper is kind of like a magic machine that can take the movie off the disc and save it onto a computer. It's like taking a picture of the movie and keeping it on your computer so you can watch it without needing the disc or the player.
So why would someone want to do this? Well, maybe they don't want to keep getting up to change the disc every time they want to watch the movie. Or maybe they want to be able to watch the movie on different devices, like a tablet or phone, but those devices can't play Blu-rays.
However, it's important to remember that ripping a movie off a Blu-ray disc is not always legal. So it's a good idea to only use a Blu-ray ripper to copy movies that you own and have the right to make a digital copy of.