I notice it got installed here too ...... with an entry in Video section of menu ...... but it does not work.
Easy solution for me too ..... uninstall 
Takes out kde-multimedia as expected.
Yup, when I opened Dragon Player and drilled down to where my videos are located they didn't load but It works by right clicking a file and then choosing Dragon Player (though it's not a very satisfactory solution )

There is an entry in my video section as well

Did you click the play icon? When I open Dragon Player, then dig through the directory tree to the location of the videos, and select one, once the selection window disappears, the loaded file shows at the bottom of the screen. I click the play icon, and the selected video starts. In other words, it does load, it just doesn't auto-play. There may be a setting to get it to auto-play, I just haven't found it.
Your opinion that right clicking a video file and selecting
Open with --> Dragon Player is not very satisfactory, is exactly the opposite of mine. To me that is the preferred method of launching any video, and moving your preferred player to the top of the list allows a single left click on the video file to open it with the pre chosen player.