The solid wood flooring he installed has large gaps. He's saying the gaps are because the condo doesn't allow any other subfloor aside from loosely spaced plywood planks (because it's a concrete building). I have never heard of anything like this before. Is he lying to my face?

This photo is the "final" subfloor.

Edit: Turns out he's lying to my face. However, does anyone know why planks like this would have been used in the first place? Is there any benefit or is it simply the absolute cheapest way of doing flooring?