Mostly it's me borrowing from the work of the brilliant and amazing couple's therapist Esther Perel, who often uses the term "eroticism" to get away from a strictly literal definition of sexuality. That *strictly literal definition of sexuality is also extremely present in asexual discourse.

A quote from Esther Perel's book The State of Affairs:

Sexual alchemy is a term I choose to use rather than “sex” because I prefer a definition of sexuality that goes beyond Bill Clinton’s—one that does not stop at a narrow repertoire of sexual acts but includes a broader understanding of the erotic mind, body, and energy.

The whole point is that it's not about creating a checklist of things it does or does not include, which people can wring their hands on and argue their way around. It's more about the poetics of someone who makes your blood run hotter.