I'm not sure how many of you actually read anything about the product, but the device is supposed to stay in the animal whether you get a passthrough shot or not. That being the case, it won't matter if you've got a high KE setup or a low one, either way the BowBug stays in the animal. To me it seems it would mess with both the FOC and POI of the arrow.

If you notice the two prongs on the end of the BowBug, these would be what cause it to stick to the animal. It is rubber banded to the arrow so it comes off easy.

It seems that for $200 you're getting more disadvantages than advantages. I'd rather save the $200 and buy something I'll have more confidence in.