Oh, well not everyone is going to like every pose. My personal choice for most useless pose for FF (and IMHO all of AChat) is "69 With Dildos" because if involved two women with strap ons sucking the strap ons.It's most likely just lazy coding to make an easy conversion from the 69's where the phallic objects aren't objects, but actual appendages with actual nerve endings, but it still means that not once did someone go "Umm guys, a strap on might look like a penis, but it doesn't work like one..."
Rukya, it's an SS pose that they've made for FF as well. For SS it's a really good pose but for FF I guess it's just weird.
The reality as we guess it is they basically swapped a few variables in a base coding of the pose. It just had a playable, but very silly result. The trick to say a SF where the F isn't wearing the strap on would be that it would have to be entirely new coding.