From your reasoning you invested your money in a wrong place. If you want gold or silver and not paper you should have invested it in real physical bullion. If there is another 9/11 or depression you want physical bullion not paper. I view things similarly as you in regards to hedging your wealth but I do it by buying physical bullion. The problem with 9/11 which I "assume" it will occur down the line, is that next one will be bigger and may create martial law. With markets crashing and recession getting closer to home another 9/11 would create chaos where anything could happen. Mortgage institutions are already feeling the pain and people are starting to worry about the future and with fear in the air a new 9/11 would create who knows what - which would be a perfect event for government to step in and pass laws and suspend the constitution to "protect" the public from itself. Market crash will take PM stocks lower even PMs themselves would probably be trashed initially but very shortly they should rebound, PM stocks might take longer but with ETFs it's hard to say what may occur while the PMs are trashed. Laws could be passed forbidding PM investment, or laws forbidding new PM purchases, who knows. You can't get your bullion out of an ETF while physical bullion you have on hand if need be.
My argument for physical is that it's a real hedge that if all the bad things do happen (I hope they don't) and you have to move or go anywheres you can take a bit of bullion with you as a protection. And if everything turns around and everything looks wonderful in the world and PMs do tank at least you have physical bullion to give to your kids (even tax free) where as ETF is ETF.