I think a large part of the mysterious seeming banter → sex transition is antinormative attitudes towards sex. For some large portion of people, the mate-seeking drive is tangled up with a desire for covertness, for which there is culturally specific[1] support.
“Romance” and “romanticism” seem to be fundamentally the (ideally mutual) intent to mate transgressively, “you and me against the world.” As I understand it, “romance” is specifically a modern Western[2] phenomenon explicitly opposed to formal statelike systems of accountability.
Trinley Goldenberg alludes to the function of banter:
flirting leads to sex is by continually ramping up sexual tension by a sort of plausible deniability of sexual interest
But the important thing to understand is why people are seeking plausible deniability. Naturally the opposition to accountability is disinclined to give an honest account of itself, so people will tend to deflect from the central question onto tangential issues like the quality of banter, or vague pointers like “sexual tension.” But if your sexuality isn’t about being naughty and getting away with something, there’s little point in mimicking the otherwise extremely inefficient plausible-deniability rituals (such as the ones described in the OP) needed to build inexplicit, covert mutual knowledge of attraction. Dancing works better for you because it is a virtue signal.
See also:
See also this thread—I don’t expect these sorts of problems to be solved by 2026, and I’ll be pleasantly surprised if I’m not constantly dealing with this sort of nonsense—or totally craven flipflopping—when asking LLMs for help with basic info by 2030.