When Bitcoin is the "only real" currency, why are Bitcoiners still talking about buying Bitcoin instead of selling fiat?

When Bitcoin is the "only real" currency, why are Bitcoiners still talking about buying Bitcoin instead of selling fiat?

And why are they talking about "Bitcoin going up" instead of "the dollar dropping"?

And why do I so often hear that gold is not a good asset. But when Bitcoin is going down, they say "gold also went down"? Does that make anything better? So you compare Bitcoin with something that is a bad asset in your logic, but use it to justify the bad performance?

It kind of shows their philosophy and points toward Bitcoin being just a speculative asset.