Hmm, in my head, I model conversation as a game of who can get the mine the most "intimacy", if you will, while revealing the least about oneself. So risque topics are, as the adjective suggests, high risk, but also high reward. Correspondingly, small talk is a lot of low risk, low reward back-and-forth. You don't have to be intimate with a stranger, but you need to stick your neck out if you want to progress beyond…
Revealing "intimate" things about yourself seems to be the easiest way for others to believe that you consider them trustworthy for almost zero cost.
"u/screye trusts me enough to tell something they are vulnerable about." Or on a more selfish note, "I now hold leverage on r/screye, so I shall continue engaging with them from a position of assumed power" or lastly, "I can share something intimate about myself with u/screye because I know something just as important seeming, so they would not use it against me"
It works surprisingly well to fast track the building of a relationship with any acquaintance.
Ofc, I put intimate in "quotes" because while the details sound intimate to the listener, they are often carefully chosen to be ones that do not cause value judgements for my current self nor are they the real insecurities (or at least not present ones) which I hold far closer to my heart. But, the person I'm talking to doesn't need to know that.