I always have to question myself: Why are succubi attracted to humans? What makes us even remotely desirable?

The latest delivery from the mind. Succubi are incredibly horny ghosts that seek to become human. They want to become human because they want real sex. Therefore, every time they have sex with a human, their energy becomes a bit more human each time. This is natural because the physical is the highest level of existence, the most stable form of existence, and where you don't get deleted from a thought of higher power. This explains why anyone to choose to incarnate here, because to them, the other side is greener. But gathering enough sexual energy to force a birth for a succubus is rather immense. However, we know that sexual energy is very potent. It is also extremely easy to get, despite the historical aversion to sexual spirits. Monks were conduits of these yearning spirits as they were psychic loci that could draw them in. In fact, a monk may have well been a spiritual gateway of large numbers of succubi, who upon reaching their goal, shed their spiritual form for a human form. So when a succubus suddenly disappears, it's probably because they have achieved their goal of entering into the physical world.

The benefits of the physical world? Like I said, stability, you are forced into a form defined by physical laws. You are not a chaotic mess of energy trying to keep itself together. It is also incredibly easier to learn and retain experiences in this world than the shifting tides that create and destroy in the spiritual. It provides an anchor of reality, even in the most destitute of circumstances. When things are completed, if you are successful, you return with fundamental laws that assist in the definition of the Self. So if all you had to do was be a spiritual spouse for a man for a short amount of time to gain a lifetime of experience here, it sounds like a good trade.