I really can't see the motivation to use such software. I realise such motivations exist, but is it really anything sexual? I don't need to undress an attractive lady to find her attractive, and I have no possible motivation to do so unless it's my lucky day and she's with me in the flesh, so to speak.
But to write such software is an entirely different kettle of fish. Visualisation is an interesting problem no matter what the subject. I've written scientific visualisation software, and it was certainly one of the more inherently worthwhile things I've worked on. As soon as news broke of an app being withdrawn, the intellectual challenge was there, and someone was bound to take it up!
In my first term as a student, one of my courses was Group Theory. I picked up and solved a 'magic cube' that was a practical exercise in the subject - entertaining but in reality peripheral to the course. A year or so later those cubes had hit the shops under the brand name Rubik's Cube. Seems to me much the same kind of intellectual exercise as re-creating this software.
 The context being satellite images. The visualisation software helped pick out many things, from seismic activity to pollution incidents to the phase of the tide.