Freemium camsites are relatively new. They have been on the rise the past decade. The concept of these free camsites can mainly be compared to crowdfunding. Many people pay a little so that you eventually get to see what the cam model has to offer. This is a numbers game and as a customer you don't expect to be one on one with the model.
Pros and cons
For a customer it is cheaper to get to see a show. A lot of the visitors don't pay anything at all. But the downside is that you won't interact that much with the model. Especially if you tipped nothing at all. For the model, it is easier to earn money, but harder to build an actual fanbase.