Sure it is. If someone steals your gold, you can call the people with guns to arrest them and get it back to you (often). It doesn't have to work 100% of the time to be an effective deterrent.

It's the same with coins.

However fiat money must be protected by people with guns against forgery. With one exception: people in power are allowed to counterfeit it, thus robbing the common people, under protection of people with guns.

Gold and Bitcoin are immune to both types of forgery.

Gold is not, and has never been, immune to forgery. Science has made it harder, but still happens all the time. See: gold plating, gold alloys, etc.

I'm not aware of any way to actually increase the total amount of real gold in/on the earth in any meaningful way in an ECONOMICAL matter (i.e. you have a net positive income from producing it). The government can make more REAL MONEY for far less than the value of the money.

That’s not forgery. That’s inflation.

You only get a net positive income for producing gold if the price is higher than the cost of production.

Counterfeit gold is a long-standing art, even to the present day https://www.thermofisher.com/blog/metals/buyer-and-seller-be...

The same thing applies to cryptocurrency. You can call up people with guns to do that too.