I though the end result was ok looking but the steel frame was so redundant, a massive, over engineered frame between elements that would stand up all by themselves without it. If the spans were massive (like in a shopping centre), or the whole thing was cantievered out over the edge of a cliff then the structure would make sense, but on a household scale its just daft. Most of that steel didn’t need to be there and the modular concept would have mostly been achieved without it.
As a retirement gift to yourself, if you’ve spent your working life building steel buildings then its ace, but I can’t see a market for selling more of them. Its a £500,000 solution to a £50,000 problem.