If I do not recommend the sales of Envato (wp theme etc.) to my customers, can I benefit from it?
Only if you are set up properly as an affiliate and if they buy an item on their first visit to the marketplace.
So can you proceed like this?
Can you give me purchasing power for every customer I bring in? I get themes from time to time.
You’d have to apply to become an affiliate (check the link above).
If you do not have a website or channel that will bring frequent traffic to envato then there is no guarantee that they would approve it.
Once an affiliate you only earn when the purchase is made on a users first visit, so if they have visited an envato marketplace previously, regardless of of they had purchased anything, then it would not be applicable.
It is the affiliate’s role to bring fresh traffic in to the marketplaces not envato.