All wood frame is not equivalent. Modern stick framing is designed to slow the spread of flame both with how the wood is used (see modern stick framing vs balloon framing) and the other materials chosen (drywall is fairly nonflammable, whereas this seems to use plywood walls). I’m not saying this is better or worse (it might be that all the insulation significantly slows the spread of flame?), but they haven’t really discussed the fire safety implications of their design that I can see.