This is simply going to make the tyres rock hard. Manufacturers can make a tyre that lasts 200,000kms already, and I think Coopers already make a few product lines with very hard compounds to lasy almost 100,000kms, they don't need a secret recipe aditive to formulate these compounds. But when cars running said tyres ended up wrapped around trees every time it rained or it got featured on "The Project" for having a tenth of the grip of a normal tyre they would stop selling them again. Tyres are a compromise longevity, wet and dry grip, noise and comfort. What a dumb video for trying to promote it as some special secret or having no ill side effects, although If I had a complete hunk of junk to test it on I probably would give it a go for giggles.
They used to do very hard compounds in the old days, I had a pair on my 1985 Golf GTI some old grandad had fitted them. It was a complete death trap, especially in the rain.
What a mong for putting on a belt, the belt won't last forwever, it'll crack and split.