In my opinion such a wall behind the fire is relatively useless and surely not reflecting anything, and I doubt a relevant remission of heat in such a distance to the shelter.
But: It keeps some wind away and the wood can dry out if you want to burn it later. Especially in the snow you always have some snow in the bark and that can be dryed away like this.
All the wood that I collected as dry as possible I usually dry totally out around the fire before I burn it. If you do that you have to pay attention of course that the fire doesn't ignite the drying wood around it.
The German Army Tent is very similar to the US Army tent and sold for very very low prices. For bushcraft it is unnecessary to buy and carry poles and metal pegs because we easily can make that stuff in the woods.
Cotton tents in general are relativly heavy but spark resistant and very long lasting.
With the tent half come 5 pole segments but on flat ground you have to use only 4 segments for each pole!
Lean to version for one person:
Open 2 man version with option to heat it with a fire in cold conditions:
One Bundeswehr (BW) tent half (BW Zeltbahn) used as rain poncho or coat: