Back in the day, and probably even now, as I used to encounter them when I lived in the big city, cam copies were famous on the streets. It was the only way to get a bootleg copy while the movie was still in theatres but you didn’t want to go for whatever reason.
When I lived in the big city, in a not so great area, the guys used to be in the grocery store parking lot or barbers or smoke shops selling the DVDs and before that were selling VHS copies.
And then when LimeWire grew in popularity, people would upload those like they would any retail DVD. And then went on to torrents as those grew in popularity.
And it still continues today for similar reasons. People want the fame that comes with uploading the first copy online or the first decent quality.