Inexpensive. I'm sure initial taste has some impact on the end product, but I've only had the rather sweet variety, either named Glüh Wein or Vin Chaud depending on where you are.
A google hit of Vin Chaud
shows that sugar and some type of strong alcohol are common ingredients.
Taken together with cloves, cinnamon, orange (zest) etc. the original flavor is overwhelmed. I'm sure that is one of the original reasons for it. In the GOT books spoilage of the wine is a reason (or am I thinking Wheel of Time?).
I've never made it myself using such a recipe. Only with the following sachet, IIRC:
Added to that besides available wine was some brandy, pieces of orange and some cloves, cinnamon if available. Sugar probably or honey.
It had great situational flavor. As in we were on a skiing holiday, were tired and 'rosy' from the sun, crashed on the couch and had some. I'm sure objectively it wasn't that great.
Matt's been in France for a couple of months (IIRC). Perhaps he or one of our French members has a better idea in the recipe thread.