how is that a problem? have you looked at the open source software movement? there are tons of near-clones of any kind of software imaginable. anyone on earth can create any software at any time. does that mean Microsoft is worthless? anyone can create any website or blog they want, does that make websites worthless? cryptocurrencies are only worth something if they are secure and people use them.* people have to expend effort and money to make a cryptocurrency worth something. yes, if you create a cryptocurrency today it'll probably be worthless, as it should be. bitcoin or any other crypto can go poof to zero overnight if they are abandoned or proven not secure.
i agree with you that gold and cryptocurrencies will be worthless if society collapses. but that doesn't make those useless non-correlated asset classes while society is running along normally. (i personally think gold is about as useless as it gets so i don't own any.)
* https://forum.mrmoneymustache.com/investor-alley/official-crypto-currency-portfolios-and-discussion/msg1706244/#msg1706244
Despite other alternatives, gold alloy is still the best material for dental work.
Gold powder is used in other medical treatments, such as for reducing swelling of arthritis.
Gold is one of the best materials for shielding ultraviolet rays; think satellites and astronaut face visors.
Gold is highly conductive and malleable, and never tarnishes. Got a cell phone or computer? Chances are there's about 50 milligrams of gold in each of them, simply because of its unique physical properties.
And of course, there's the obvious applications in jewelry and building materials, etc., for anything from modest to extravagant expressions of love or wealth.
I'm sure there's other examples; but hopefully you get my point. It's not just an otherwise valueless metal that sits as inert bricks in a vault. Its unique properties give it an intrinsic value that goes far beyond just a betting chip for speculators.
Bitcoin, as a payment system, is inferior, on balance, to existing systems. Sure, that's just my opinion, and I'm sure it's debatable.
Leaving that aside, what else can I do with a bitcoin, other than sell it to someone willing to pay a higher price than I did?
If society collapses, gold will still retain intrinsic value that will remain unexploited, but only until society rebuilds itself. Golds unique physical properties do not depend on any specific social structure.
Case in point: Confederates who used Confederate dollars to buy gold had an asset that was valuable long after the war was lost to the Union. Any who held on to paper currency found that their money simply expired, valueless, six months after the war was lost.
If society collapses permanently, then yeah, it's a moot point in any case.