To make the textures look like they look when they’re created. Also better performance in 2D games. A good engine should have switches on and off for everything, so that people can configure and get the best out of it. It’s a good development approach and is known as a “feature flag”.
It is possible.
Well, this will change how the textures look and they won’t look like they are when they were created. It’s very important for 2D games to preserve the original look of how it looked when they were created in image editing software.
Not really. It looks more different to the original look, so it’s not better, just different. Which is worse for 2D games.