That was so thermal I think I got a little crispy.

It isn't misinformation. Wifi just doesn't perform as well as wired connection. That doesn't mean that you can't get a good Wifi connection. If your Playstation is right next to the router, it probably won't be a noticeable difference. If you move too far away from the router, you'll definitely notice degradation in performance.

You might be the outlier here, but generally, there is a massive difference between the two. I went from 1MBPS on wifi to well over 9 when wired. That's without any of the further optimizations I've done on the network since. Generally speaking, in 99 out of 100 cases, most people will see a marked increase in performance with a physical connection.

Most likely that there is. Your wireless will almost always have more latency. You might not be able to tell the difference, but if someone else pings your console when it's in and out of WiFi you should be able to measure the difference. You're still probably less than 100 ms on the WiFi if you can't tell the difference, but hard connection will be marginally to greatly faster depending on the quality of your wireless. If for some reason your setup is the exception to the rule, I have no idea. But for most others thus will not be the case :)