No. Sorry about that Ken from Oakville, Ontario.
If the garage is unheated, insulating the door will not make the room any warmer. Insulation does not make heat it just helps to hold it in. Good weather-stripping on that door may help a little, simply because cold air drafts can wipe the underside of that bedroom with cold air making it colder than simply having a cold room below. If however, the entire room is already insulated, especially if it is insulated even better than the wall to the house, then insulating the door could help because then heat losses from the house could be trapped here and although it will not end up warm, it can end up considerably warmer than the outdoors.
You are much better off air sealing all around the garage up in the floor joist area and then working on insulating the ceiling. The reality is that no matter how much insulation you put into ceiling of the garage, a room above an unheated space will always have a colder floor than a room over a heated space. That is not bad for a bedroom where we can have thick rugs and don't stand around on the floor much. But don't try to put that home office over an unheated garage. You will always have cold feet.
If you are going to heat the garage, then that insulated door becomes an essential part of the whole insulation project.