Yes, there are different stages to a sales funnel, and you need each one of them. This is not only having 3 pages. There is a lot more to it.
You see, sales funnels is such an important marketing action that you cannot go without having it.
Without a sales funnel, you are just doing random stuff. Most of the time, this random stuff does not work.
When you define your funnel into a top, middle and bottom of the funnel your marketing and your sales become a lot clearer.
Here is a video where I go over more details about a sales funnel.