Hmmm. That brick is an interesting concept. Haven't seen that before in an RV, or a house, except around fireplaces and wood burning stoves!
Maybe the brick helps keep the temperature more constant? I have what I call a 'hot rock'. It's just a big river rock that I put a towel around. I sometimes warm up the rock and put it in the towel and put the rock in the bed with me to help keep warm, as the rock radiates heat for quite some time before it cools off. Maybe the brick is serving the same purpose in the camper furnace?