I've bought and sold on Craigslist.
On CL, as a seller, I list on the local CL and as a buyer, I shop from sellers in locations that are reasonable distances that I'm willing to travel. Your comment of "having to GO SOMEWHERE" being beyond most people's schedules sounds nutty to me, but perhaps that's because as a baby boomer, I'm used to finding or making time for what I want to do. Even now, I don't do most of my shopping online; I shop at B&M stores so going to meet someone to buy or sell something isn't that different.
In each case, transactions were for cash and the buyer could examine the item in person before handing over the money.
There were a few instances where I bought or sold large items that couldn't be exchanged at Dunkin Donuts or McDonald's. In those cases, I wouldn't go alone to someone's house so I wouldn't be alone when someone would come to look at the large item.
I've never had a problem but I've never done a large (megabucks) type of transaction.