I have a very close friend who worked for a couple years as a sex worker. She left the job completely alienated from her body to the point where she was unable to achieve orgasm. Now, there are other contributing factors to this, so I'm not saying it was just the intimacy thing. She was beaten and brutally sexually assaulted multiple times, ie. But she also firmly believes that treating sex as a detached, clinical, act damaged her spirit and disconnected her from her body and her feelings. Which is exactly what I would expect to happen if there was something inherently intimate about it.
And I am sure that many (most? all?) sex workers have had traumatic sexual experiences (as have, statistically, AT LEAST 20% of women) - which is why I added the qualifier "do all...?). Each person's experience is different. Perhaps some turn to sex work to "make the most", monetarily,from the fact that they view themselves as broken. Perhaps some are trying to "take back" control of their sexuality. And so many other scenarios.
Disclaimer: I have never been a sex worker, I do have a friend who was a Pro-Domme. I have an interest in whether there is such a thing as "healthy" sex work - I think it may exist. LOTS of people enjoy performing Burlesque - bawdy and fun, where does that slide into "stripping"? Are "ShowGirls" performers or sex workers? If you titillate but don't "put out" where does that fall on the spectrum of "slut"? Why? and is that "fair"?