I wonder how many would actually follow it to try.. Your speed will always be limited by the speed provisioned to you by the ISP.
As for what you get.. depending on the company, some might get a time of day congestion which could slow down your own speed significantly.
Though if it's just a trick to see if people are gullible enough to believe , "put the battery about 3 inches from the end facing either way, and then we use electrical tape because it conducts electricity" (electrical tape is an insulator, won't conduct). You could just turn on your router's bandwidth control and thottle your own speed for a show.
You obviously missed the description under the video itself.
How to get a faster internet connection from your internet service provider using troll science! This trick has a zero percent chance of improving your internet and download speeds. Please stop asking me why you can't get faster speeds because you need to just buy it. Send this to your tech-savvy friends for a laugh! Your internet speed can't actually be increased, you'll have to upgrade your plan.
He did the video in response to people asking him HOW they can get faster speeds. It was a complete joke.