CL is a pain in the back in my limited experience. Admittedly, I don't know cars well - I think to a degree that's a necessity to buy stuff off Craigslist. You have to be able to look at a car, pop a hood, go for a test spin, and feel out the trouble spots. Otherwise, you have to bring car to mechanic you trust to inspect, which is a pain, and many sellers don't like doing.
Ime, is mainly (after you filter by owner only) off the books dealers, scammers, and people trying to sell their car for the top KBB private sale value. The scammers cars generally don't exist. If you browse enough, you get a feel for their listings, and can tell as soon as you open it that it's a scam. They often don't want to speak on phone, have weird stories behind cars, have images that look professional dealer photos or from clearly a different locale than the car is supposedly located in (like palm trees and a gorgeous house for a car in NYC), and just straight up weird prices (like $7,208) and descriptions.
The actual private sellers are pretty annoying and non cooperative. Chances are they've been flooded with a million garbage offers and scam messages too, and are wary. CL is a cesspool. They're cars are often overpriced, arranging a meeting is a pain, the cars won't have license plates and they won't want you to take a test drive or get inspection, and there will be a catch. CL is garbage. Always assume there's a catch. If it's too good to be true, you haven't looked deep enough.
In a way, the shady fake cash only dealers/flippers are the easiest to work with. That being said, there's a reason why they're cash only and operating under fake names on CL. There's no recourse once you buy that car. There will be no real bill of sale, no documentation, no warranty, and no lemon law protection. Chances are the title is still in the name of person they got car from. Make sure to inspect car very carefully, because there's no backsies. These guys know the business, and the cars are priced the way they are for a reason. They bought some junker, did a cheap sloppy job putting lipstick on the pig, and try to pass it off to the next naive buyer. Be aware of this going in. Caveat emptor.
First thing I always did before setting a meeting to see car was ask for VIN to check vehicle history. If they don't provide, I ignore. Chances are car has been in 3 major accidents and has odometer rolled back 100k.
I also confirm that I can bring car to mechanic nearby to inspect. If they don't allow, that's deal breaker red flag in my book.
Wherever I do schedule a meeting, I try to get there early to check out car externally without guy breathing over shoulder and spewing distracting garbage whenever I see area of concern. That's more me by personality - I'm pretty non confrontational. Could be it's not really necessary. I've definitely ghosted meetups after seeing car in person and just walking away.
I've bought a few cars on CL in $1k-$5k range, and while not pretty, they've done fairly well mechanically. I definitely can't complain. That being said, it's a real pain to filter through all the absolute garbage there. Actual deals are rare, though, in my limited experience.