1. The paper trail is probably not as good as you think. I feel like you're thinking of a US system where there might be some pretty solid systems in place, but what about all the other countries around the world? I'm sure there will be at least a few places that will not be great paper trails.
2. The paper trail only helps you after you've been scammed as a way to maybe track down whoever did that. A costly and time consuming process which may be next to impossible if you think about the complications of shell companies and legal jurisdictions. Or are you suggesting that before you use a site you go through all this work proactively?