The studs are obviously not good everywhere. A place where there is lots of slab rock, probably not. But that guy does make it up that ledge and it looks like the studs grabbed on to the edge pretty well; he may have does just as well with all rubber. The other guy going up the loam slope looks to benefit quite a lot from his rear tire spikes and yes at night you can see the sparks. If he could just get his brakes working he would be golden
I've heard that spiky chains work well in rocks too. These studs are going to be a lot lighter than chains and for this style of rig and wheeling I don't think chains would work. Too much HP and wheel spin.
I'd say, without trying them, the studded tires would work well in woods terrain with lots of soil and mud and logs, more Midwestern, Southeastern 4 wheeling, which is where it looks like lots of these high horse power buggies play, and not so much for west of the Rockies wheeling.
My experience with spiked (sheetmetal screws through the tires) mountain bike tires offered more traction on hard frozen ground and ice than no spikes on dry ground in the summer.
If they aren't something you can buy then it looks like you could construct them from stainless steel hardware with perhaps capped lug-nuts.