While I don't doubt that creating a plethora of nucleation sites would create a creamy head in a beer with rather low carbonation, the rest of that article is bologna.
Nitrogen is NOT used because it goes into solution. Rather, it is used because it DOES NOT go into solution (easily). Therefore, the beer can be held and served at high pressure AND a state of low carbonation.
The restrictor plate in a stout faucet needs high pressure beer to be forced through it to work correctly. As the beer passes through the restrictor plate, CO2 comes out of solution in tiny bubbles, making the creamy head. The low carbonation of the underlying beer gives it a silky mouthfeel.
The widget is basically a ping pong ball with a small hole in it. When the beer is bottled/canned, it is carbonated at a low level, then capped under high pressure as a result of the introduction of nitrogen. Under pressure, BEER is forced into that small hole in the widget. When the top is popped, the BEER is forced through the hole, causing CO2 to come out of solution in much the same way as it would through the restrictor plate in a stout faucet.
I've read some articles that claim that the small (MINUTE) amount of nitrogen that is dissolved in the beer does stabilize the head. Even if that is true, nitrogen is not the chief actor in the stout pour process. That role still belongs to CO2. Nitrogen is an enabler.