The reason I would embed YouTube on my own site is that I'm assuming that most viewers would watch it without clicking through to YouTube. Then, if they choose to purchase the $25 DVD, it's natural to follow the buy link on my site, which will direct them to Paypal and net me $23.98. If, on the other hand, there is a buy link in the trailer itself, they will just as likely click on that, and their purchase through Distrify will only net me $17.50.
Encountering the trailer on Facebook, a blog, or some other site, is naturally a different situation.
Regarding ZashPay, is the $1 fee their 75¢ fee + 25¢ to Distrify?
It would be good if there was a more obvious link to the filmmaker's site in the app. Many buyers want to learn more about the film beyond the trailer before purchasing. Doing a Google search for the title is one more step that may be considered to be not worth their while in the midst of a busy day. The fact that the share link brings them to my site would not help in such a case.