Several GoldWingers have tried that. They generally have mounted them on their trailer. None have found it successful. The problems are:
It only cools to about 40F below the outside temperature.
If it is exposed to the sun it probably not be able to overcome the solar heating.
It requires a higher output alternator than stock to meet the additional load.
It will deplete a MC battery quickly when the engine is not running.
Items placed in it must already be cool, it will take forever to cool warm items.
It has a lot of weight/size for it's capacity.
Several years ago I bought one to use in in my pickup. I kept it in the shade behind the seat in the extra-cab portion. It didn't have to work too hard because I kept the cab cool with the air-conditioning. It was plugged in all the time, even when the engine was not running. I was disappointed with it's performance and changed back to an ice-chest and ice. Although items were cool, they didn't have that "cold" feeling that is so important on a hot day (I was fighting forest fires and a really cold drink was very important!). And the 12v. cooler would not hold enough to keep myself and my crew supplied. The ice-chest held more at the start of the day and would cool new stuff within an hour, when the items were buried in the ice. We did have an unlimited supply of ice each morning. If I were in a 4-wheel vehicle, with room and power for it, somewhere where ice would not be available for a long time (the Sahara?) I might use one, but otherwise in general I can't recommend them.