What's up with the scroll bars?

[Parody]

OK, so I'm finally asking my most burning question about how Realm Works looks and works, one I've had since I first installed it:

What's up with the narrow scroll thumbs and various other minor changes in the scroll bars?

I know they're almost completely cosmetic, notably the narrow thumb. (You can grab the thumb to the left or right of the narrow visible strip.) I'm just wondering if there's an interesting reason why this look was chosen.

Inquiring minds want to know! Well, one mind anyway. ;)