YouTube takes into account lots of different factors when it ranks videos and one of the important factors is the number of times the video has been viewed.
Of course, since YouTube is owned by Google, it's not quite as simple as that. So you can't just go out and buy a bunch of views from Fiverr and hope that you can fool YouTube into thinking you're more popular than you really are.
In fact, that's a good way to get your video (or even your whole account) deleted....