The last part of that video with the fellow pulling the trailer with the sheath of grain (oats?) tied across it illustrates one issue with two wheel bike tailers and trikes...namely that the combination is a three track vehicle which can be problematic on roads established by and for two track vehicles. In order to keep that trailer on the road, the rider is forced in many instances to steer the bike over rough and rocky sections in the middle of the road.
I use a two wheeled cargo trailer, but this is a downside that should be considered.