BAP is 6-Benzylaminopurine. You asked!
It's a member of a family of naturally occurring plant hormones that can cause plants to readily grow. If you, for example, apply it to the cut when dividing fans, it will coax additional fans through new growing points. It can also be used on the bracts of a scape to induce proliferations. There are some who have found or believe that when BAP is applied to plants the new plants will not bloom or set seed for a while. This has not been my experience in the small amount I have experimented with BAP.
As to your second question, you could sell the plant for whatever you wanted. I have found that daylily people are often kind and generous and I try to be a fitting member of the community. In a case like you describe Mayo, I would likely just grow the plant to see it bloom because photos often do not capture the full beauty of the plant. If I didn't like it then, or didn't want to work with it, I might trade the fans for something I like. Or try and use it to pay it forward (which usually means my mother gets it since she pretty much gets first dibs).