That’s the real dilemma. KU does get you exposure. Because subscribers can read any KU book for free, they’re able to gamble on new names, or new genres. And if they like your work, the odds are they’ll be less hesitant to buy something from Amazon that isn’t a free KU read. Especially in the romance genre, readers are looking for new things, and erotica is not so much of a closeted genre anymore, either. It’s a risk, but it can pay off. You would just need to be willing not to make much profit from the KU offering. (On the other hand, if you are in the US and consider your writing a business, it’s a business expense you can deduct against any actual profits, just like the cost of cover art, editing, proofreading, and so on. You just need to show some actual revenue, and I suppose even $10 counts. )