"Both” is probably the better answer.

Gold has the advantage of centuries of monetary trust and, as Darrel points out, countries like China have a strategic reason to accumulate something outside the dollar system.

Bitcoin offers something gold can't, a globally transferable, verifiable scarce asset that doesn't require moving tons of metal between vaults.

Maybe this isn't gold vs bitcoin...gold may be what nations trust during the transition, while bitcoin is what eventually changes what a reserve asset can be.