If the wall gets a lot of sun, you might be able to reduce the heat transfer, but your biggest insulating loss will be with the garage door and you may not see any advantageYou won't trap condensation so that shouldn't enter the equationA room does not need to be heated or air conditioned to benefit from insulation.
sorry but i think that a lot of people mostly americans,always try to find a hidden deep moral meaning to a film,rather than just accepting a film for what it is,A FILM.
You should not insulate unheated spacesThere's simply no point, and it can trap condensation.
