I take his UV talk with a grain of salt and far from absolute fact or gospel.
UV is very tricky. Not all sources are equal. He didn't show what he used and how he used it leaving me with questions. It's one thing to introduce 395 to 420 nm to a grow, it's a whole other issue between sourcing and power of it.
For example, floro and LED might both 400nm but they're two totally different animals in regards to height over target, coverage, and power used to deploy it.
I could use a 40 watt reptile light and conclude it doesn't do anything. I could also use a 70 watt LED array and conclude it works every time all the time. The more people use it the more we'll find what's the best source and how to best apply it to get benefit from it.
Already, aside from xtra resin claims, I've found one of it's benefits is making a garden less desirable to pests. I'm about 60/40 on it increasing potency but around 95% on it's effectiveness to deter pests.