I really, really like this behavior on mobile, especially on sites that dynamically load new content as I scroll down. I honestly don't understand the harsh cri

I really, really like this behavior on mobile, especially on sites that dynamically load new content as I scroll down. I honestly don't understand the harsh criticism I'm seeing in the comments here, because this really is a super functional way of giving the user easy access to navigation controls without having to scroll all the way to the top of a page. That said, I suppose I can understand criticism if this were being used in cases where there generally wasn't a lot of content to scroll through. I guess my point is, like all design decisions, it completely depends on the use case as to whether or not this is useful or functional.