Because chunks of it start coming up from wear and tear and the only thing worse than not having anti reflective coating is having bits and pieces of your display reflective and the rest of it nonreflective.
Took a bit longer than 10 minutes but baking soda paste definitely did the trick. Thanks for this comment. All I do on this laptop is surf the web and send texts on iMessage so you just bought me a lot of time before I need to upgrade.