That’s gold bullion

which is only one form of gold. And frankly, not really the form of gold that common folk would ever have. But owning gold coin has never been illegal. Even if it was, I’d like to see them enforce it. It’s the day-to-day trading value of gold coin that keeps that form of currency alive even in modern developed nations regardless of who is in power at any given time.
There are a lot of pro’s and con’s, as I’ve listed and as other folks have pointed out. But I take history to be my teacher on this one. The USA is a very young country, and has not had the upheavals that other societies and cultures have had. Those societies have repeatedly either gone to, or gone BACK to, the gold/silver standard whenever their own currency stumbled badly. It has happened on every continent where human civilization has existed, repeatedly, for 6000 years. That sort of track record counts for something which I doubt has changed in the last 200 years, even if our nation has not itself ever experienced those types of events. If the USA has a big weak spot, it’s that we as a society haven’t gone through a serious national crisis as have many (most?) other nations. We’re like the teenager who’s had a driver’s license for 18 months, and hasn’t seen any serious accidents or had any close calls, so can’t imagine it’ll ever actually happen to us. But looking to other societies and how they handled long-term economic upheaval, and that gold/silver standard shows up every single time. Hard to argue with that.

One other draw back

I forgot to list earlier. When times have gotten rough in the past the US government has declared it illegal to own gold bullion (from 1933 to 1974 it was illegal for U.S. citizens to own gold in the form of gold bullion, without a special license) and took it from everyone that did not have that license. If they did it once, there is nothing to keep them from doing it again. They might change the currency, they’ve done that more than once, but they have always done a replacement for the old currency with the new currency.