The most sleazy thing it does is that if you want to download or share an image with your friends in, say, a text chain, it brands that image with Reddit crap.
They go completely out of their way to make the app unusable.
It's a stupid idea that brings them no value and it's user-hostile.
I didn't realize it could be turned off though! I guess that's useful for when I hold my nose and scroll quickly through the meme subreddits to find things for my meme text chains.