Thank you all for your time and your answers. As Robert guessed, I already know HOW to earn points but I meant I don't see WHY ! Robert and Phylis answered me partially and I thank them again. By the way Robert, I like your spirit of synthesis ;-)
After 2 ou 3 monthes among you, I perceived that motivations of members can be various. Some are here to sell ( I see no disdvantage ), some to learn ( my case), some to exchange and socialy communicate, and some just to watch. Visibilty is essential for the first one mainly and partially to learn. I found that in this site, the two ways to have it is FP and weekly them, because images are exposed inthe real showcase. When an external visitor is coming, it is his first and only first step.
Concerning me, I'd be happy to sell some images ( already did once here), and I have a lot to learn. As I don't like policy, this excludes weekly theme, and the only stuff that motivate me are publication and my curation and critics activity, therefore my analysis activity. The system is efficient as I trust the official curators. but unfortunately this is not always the case, and I feel that objectivity is periodic, or not constant and sometimes not coherent (another topic), and I really hope this has nothing to do with politics. As long as I'm a member I accept the rules, but I keep thinking about it.
About points... as said Robert (my reference again ;-)) Despite Phyllis explanations about place in some lists, I'm not sure that the system of points improves visibility. As I can see, it stimulates the activity of some members on the site, which serves mainly the founders.
It's not pejorative, it's just my feeling of new member, and I hope it will be helpful.