They have to do this anyways when you choose to delete their account. And according to Zuckerberg's testimony, he is very confident that this functionality works very well currently.
Yes, it would make a difference there. My question is in regards to the top-level comment, will people notice the difference?
For example: If my mother "cleared her history", I really doubt she would notice the worse quality of Facebook and regret deleting her data, as the top-level comment implied. So my point is it's not a move to show how effective the algorithms are, but a privacy-conscious one from Facebook.
