..... I am just a bit skeptical.....
I am extremely skeptical. One thing to keep in mind is that any material impermeable enough to hold argon would presumably also be impermeable to water vapor. In other words, this clothing would likely not be "breathable" at all.
Also, one would also need to carry the "Quickshot" refill cannisters and "Klymitizer" valve to adjust the amount of argon filling. Interestingly enough, the website fails to note the weight of these accessories.
It all looks like a pile of steer poop to me.