I feel like most of the most of the people here didn’t read the article or watch the video. If you’re asking “why would anyone need this”, the article touches on it:

One of Lenovo’s big ideas is that the form factor could be useful for digital artists, helping them to see the world behind the laptop’s screen while sketching it on the lower half of the laptop where the keyboard is[…]

Also, it’s a prototype, yet people are responding as if this is a product that Lenovo is launching. Even if transparent screens do become a popular but useless fad, that wouldn’t nullify the value of this prototype. Trying shit is fun, especially if it’s something we’ve been imagining in sci-fi for years!