I did some SEO for a local landscape company. They were already doing well, but asked me about doing ads on FB. I told them I thought it was a scam, but they persisted so I ran a few campaigns for irrigation in the Spring and then fall cleanup starting in August.
Same thing happened. They got a ton of impressions and clicks (no surprise) and a about a dozen leads. When they went through them, nearly all were for fake numbers (no answer and no VM) or email addresses that bounced. They ended up with one lead for a service they don't even make any money on.
In the end, they lost a few hundred dollars, but it was enough to convince them running FB ads to generate business was not only a good idea, but it convinced them it was rigged and a scam.