I also tried to monetize my DP channel but roku has a terrible support for developers. I have about 2K viewers per day. I haven't got any stats for my ads at all. I emailed them multiple times and they told me that they would set up reports which will be emailed to me. But of course nothing happened. So i disabled ads. Is there any alternative ad networks that i can test?
With this kind of developer support Roku will fail soon or later. Even the developer website has so many problems. I don't understand how they became so popular at all.