I just read some people's jorney about how they earned money through Cleanfiles/Sharecash/FileIce and I thought I'd start myself. However, searching further, some people dissuaded and claimed that CPA is a much better choice (because PPD serves as a middleman). But I don't understand, if you earn more with CPA, why are people using PPD? I searched and it seems that the only pro of using PPD over CPA is that PPD is easier to use?