I understand, though there is a marked difference between the couple of dozen European troops deployed in this fashion and the 25,000 US soldiers deployed in Korea.
In any case, the point stands: I would argue that France is willing to put a dozen soldiers in Greenland because it is pretty sure that they won’t be killed by the US, as opposed to sending even a single soldier to Kiev where there is a reasonable chance that they might get killed and we might have to do more than just send money and guns.
The amount of money and guns that have been sent to Ukraine have been critical to its survival. They still have a functioning economy just because of all the financial aid they've received. It would obviously be better if French, British, or German troops were in Ukraine, even if they were just securing the rear areas. But the fact that no one in Europe has voluntarily joined Ukraine's war against Russia isn't comparable to putting a tripwire deterrent in place.
If the U.S. seized Nuuk, and Europe mustered a counter-invasion, it would be comparable.
In any case, the point stands: I would argue that France is willing to put a dozen soldiers in Greenland because it is pretty sure that they won’t be killed by the US, as opposed to sending even a single soldier to Kiev where there is a reasonable chance that they might get killed and we might have to do more than just send money and guns.