I've been there many times. I have a fwb that enjoys it.
It's predominantly an older crowd, but younger couples do come in. But that doesn't mean you get to have sex with them, there has to be attraction.
There's Young Swingers nights for younger couples, but you have to be under 35.
Sex workers do go there with clients, some are open to others fucking them, some not.
They usually stand out because they don't have the vibe of a genuine couple.
The big difference is: People go to CCK because they genuinely enjoy having fun sex with others.
Compared to a sex worker that fakes their enjoyment because you are paying them.
So you get all types that go there. But they are not going there because they are 'hot', it doesn't work like that.