Like dollars, euros, pounds, etc...
It's controlled issuance schedule and two the hash scarcity from mining. You can clone a coin a million times but you cannot duplicate hash scarcity.
What if it wasn't just two widely held and distributed elements they had to corner the market on and maintain supply control for, but practically any arbitrary blockchain that someone believes is necessary given the lack of availability in the other forms of money in present circulation. It makes it much harder to manufacture recessions when your target audience can simply mint their own uncensorable high quality cryptocurrency out of widely available code by simply tweaking a few variables to fit their purposes.
At the same time it doesn't take away from the value proposition of more established cryptocurrencies, because it is always obvious that these alternative chains are not units of the original currencies from which they were spawned. If people truly are simply trying to pointlessly expand the money supply for no reason, then the market will eventually punish them as that money is used in economically unproductive pursuits.
When all is said and done, a blockchain is just a globally available tamperproof digital ledger. And given that territory, you can build any given economy on top of it.