That's a good question. I don't know exactly why, but it was partly the desire to get in on the action of the trend toward legalizing MJ, and yield being high due to the novelty ( and commensurate risk ) of the land usage.
There is also call protection for a few years more, and the feeling that rate hikes by the Fed are about done for now. And the Prefered is a little less volatile than the common, plus higher on the creditor totem pole.
Not a great explanation, I know, but that's what crossed my mind upon reading your post.
Further, I bought only a small amount, so my risk exposure was not significant compared to my overall portfolio.