As was mentioned by someone else above, I suspect it's because on the more "roll of the dice" classifieds sites the bait and switch operators, and scammers, will generally be face out, with stolen pics. They have no privacy concerns with that, unlike many other sex workers. Face out on photos, especially photos that are a little too pro, with no supporting links to things like socials, and few credible reviews, is a red flag for many. Or at least requires reverse image search, and more investigation, making it a yellow flag for many others. A discerning eye, reverse image search, and research is a lot more work than just saying, "face out and looks a little too good so it's gotta be fake."
When I'm out of the GTA, in smaller cities with no agencies and few reviews, I've had decent luck on classifieds sites (LL) but I "do the work". You'd be a no brainer because there's a lot of supporting evidence that you are you. Many other providers not so much.
Pro tip for sex workers: A single shot with some local merch, or a local landmark, that a middle aged or older local guy would recognize, is a great idea. Maybe throw on that OHL jersey for the local team, or take that selfie in front of city hall. That kind of thing goes a long way to saying, "I'm for real."
