My wife uses the silver clay, and I have made pen furniture in bronze.
If sufficiently sintered, the bronze can be quite strong. I have tried to use it as an engineering material, but there are problems. The bronze needs to be kiln fired for two cycles. The first to 350c burns off the binder, then cool it, cover in charcoal to stop oxidation, then sinter for 50 mins at 810C. The shrinkage in one type of bronze is 10%, another 15%, but different firings using the same cycle on parts moulded in the same moulds can give a 3% different shrinkage. So it is impossible to make final shape parts. This is infuriating, and I have wasted a huge amount of time trying to get it to work.
Also, making the moulded parts is not fast. It is rare for the final result to be completely water tight first firing, and if the material is over worked, you can mould in air, which causes blisters and spalling. Finally, the material is about 5x the cost of phosphor bronze volume for volume.
I think it's suitable for luxury items where the extra cost & time can be paid for, but not models.
Regards
Richard