[Blender] Texturing technique with lamps and square plane mat

[Lonecat Nekophrodite]

Does anyone here try applying textures using lamps and a square mat like this one?

1. Is it neccessary to use a plane mat to do texturing so photorealism could be achieved? Rightnow I've finished UV Mapping and about to apply textures?
2. If so. Do I need to disassemble the pieces (For example to make a bronze mortar barrel shown here I have to lift the gun to the mat before applying textures?) and apply textures to each of separate components?
And Is this technique good when doing Civ6 unit models?