Why do people want SUBSCRIBERS on their channel?

Most people use services like vagex, viewet, u2bviews etc to get subscribers. What good does it do? Unless these subscribers are targeted I don't think this would do any much good or would it?

Being a subscriber of someone's channel means that I will be notified whenever they upload a new video right? So you guys use one channel to upload all your videos to promote your CPA offers? If the channel gets banned, all of the subscribers are gone right?

Is just to make the numbers look bigger, basicly if you see a channel with more subscribers, you will tend to click subscribers then in a channel with 5 subscribers.