I didn't watch the videos but chain cleaner definitely works and the chain wax is great on your chain and it lasts a long time and it's not messy. The one downside is that it is more expensive than WD40. Personally, I have no doubt that WD40 and gear oil work just fine as they're all petroleum based products that do basically the same thing...the difference is how long it lasts and the cost. I don't think WD40 is detrimental to the chain either.IDK how much stock people here put into his videos, but Fortnine did a whole video on chain cleaners and lubes. Personally I've just been using WD40 and gear oil for the last two years and have had great success with them.