It seems to move some stuff, lock a few things in place (the chat frames apparently don't like the edge of the screen in the default UI) The Action Bars in the compilation prolly move the,selves where they're wanted. If I remember, Haste plays entirely with keybinds and has no action bars showing (or used to...)
If loading it makes no visual change in your UI, I'd just turn it off.
Any addons that need a library should already have them embedded. If you don't know the difference between embedded libraries and standalone libraries, and don't know why you would use one over the other, just stick with the embedded package, which is how addons are downloaded from release sites, and does not require (or even benefit from, in the majority of cases) any libraries to appear on their own in the addons folder.
Having standalone libraries in a in a "complete UI" package kinda makes sense, given several addons use them.
But unless it's using all standalone libraries, it's pointless, wasteful, and confusing to have standalone copies of just a few libraries while keeping the embedded copies in every addon. It's not the user's fault, but it is an all-too-common problem with the compilation uploader failing to understand how libraries and addons actually work. :p