Additionally, even without exchanges bitcoin is still capable of acting as a standalone currency. It's not currently in wide use as a standalonne currency, but like gold it doesn't necessarily have to be exchanged.
Without exchanges the price crashes. Looks what happened to Russian stocks when trading halted.
I think this could've been true a few years ago. At this point bitcoin has grown to a size that would make it virtually impossible for any government to shut down. Governments can make its usage more difficult for sure, but shutting down would require seizing the majority of bitcoin nodes across the world. These nodes are also mobile and can be moved across continents at any time.
I think you're dramatically underestimating the ruthlessness of governments.
Read about executive order 6102.
Individual gold storage was certainly "decentralized" across the entire country, but that didn't stop the government from taking country wide coordinated action.
In many ways shutting down bitcoin would be easier than executive order 6102 was, because nodes need to continually advertise themselves in order to be useful. With gold bullion, someone could hire a guy to do a job, pay in gold and there may be no records and no internet traffic associated with the event. With bitcoin, the person has to go out and check the blockchain to make sure they're not getting ripped off.
Order 6102 isn't the only example of large scale coordinated action taken by a government. Governments have been doing big things out of the blue for thousand of years. Order 6102 would have been a piece of cake compared to things like:
October 13, 1307
December 17, 1862
December 7, 1941
January 30, 1968
December 24, 1979
Large scale action is just one of those things governments do sometimes. Think about the resources summoned up for the events above.
The idea that bitcoin could not possibly be shut down is simply a failure of imagination. No they could not seize all the bitcoin, but they don't have to. They just have to crash the value and make it extremely dangerous to transact in. Even if they don't shut down all the nodes, they can require all ISPs to report everyone communicating with one.
International boundaries complicate matters a bit, but they're not some magic force field. For example, Israel was willing to roll tanks right into Jordan and break open the vault of a bank that was engaged in terrorist financing. They even dropped a bomb on the bank president's house for good measure.
Is some random ISP going to risk a foreign hit squad in order to keep your bitcoin node or VPN link up and running? I think not.
It think this sums up the actual reality well.
https://xkcd.com/538/
I think a small allocation to gold can be reasonable in some circumstances. Assuming that it's actual, physical gold. You can easily imagine how having 10% of ones wealth in gold, as a jew in 1940's europe might have been just the ticket for getting out of town and saving your life. India has the largest per capita gold ownership in the world for a reason.
I would suggest one not plan to get rich by holding gold. It's value seems to have stayed relatively flat over a couple thousand years.