it has a fixed supply so as the supply of dollars are increased it requires more dollars to purchase as time goes on.
as an asset it’s fine, since you can buy it and it’ll presumably grow in value and you can sell it later at a higher cost. if you bought it at market value for its worth, anyway.
as a currency it’s pretty bad. if a gold coin can buy you one sandwich but next year it can buy two sandwiches, the sandwich guy just went from making one gold per sandwich to half a gold. so, not so great for economic growth to constantly be having to pay people less and less. fixed currencies don’t really make sense anyway, it doesn’t account for growth.
this is where an inflationary currency works better. as the economy grows, print more to reflect it.