I heard about this, if I had more room (like a big garage/warehouse) I would totally consider it. Makes some fun Youtube content, and could get some interesting stuff.
Could also be a great way to get good at fixing stuff. I imagine a lot of stuff like electronics may have been returned because it was not working or had an issue, but in some cases it might not be a huge issue to fix, just that if you bought something new and paid for it you'll more than likely return it and not try to fix it yourself.