I'm not saying to stop Star Trek books. but if they go trade where it's not needed, then I do think sales will drop as people who dislike trade will not purchase or not purchase as much. Also given the way eBook prices are at present, trade will increase eBook prices as well. So overall, going trade where trade is not needed is a lose-lose situation overall. I do understand trade when the word count is high enough. But otherwise, forget it.
But it doesn't matter if sales go down a little bit, because they make more money per copy sold. And you only have your guess that the sales will go down too much, with no evidence at all, when a ton of (admittedly circumstantial) evidence shows that trades DO make more money.
So, tough shit. Deal with it.