> The USD is a reserve currency which has many profound effects associated with that it is not a "bubble" asset class at this point.
That is the definition of a bubble. If people buy Tesla because they think others want to buy Tesla stocks rather than thinking the company will do well, then Tesla stocks are in a bubble. The same thing applies to USD. It being a reserve currency means it can keep its value without having assets backing up that value, that is how we define a bubble. Of course bubbles can last a long while, which is probably what you mean, but it is still a bubble and it will pop at some point.
Another reserve currency right now are bitcoins. Bitcoins being used as a reserve currency means people buy it to keep the value high, so that their savings doesn't go to waste. I'd still argue that bitcoins are a bubble, like the USD.
Absolutely and literally not a bubble - your definition is in fact, not a bubble:
"It being a reserve currency means it can keep its value without having assets backing up that value, that is how we define a bubble".
FYI: Money has three functions: a store of value, medium of exchange and a unit of account. Fiat currency does not have assets backing it up for that you would need the gold standard that we abandoned in in the 70s.
A bubble:
"Bubble, in an economic context, generally refers to a situation where the price for something—an individual stock, a financial asset, or even an entire sector, market, or asset class—exceeds its fundamental value by a large margin."
And to your bitcoin comment: not even the slightest - bitcoin is not money it does not have the same functions it is a speculative asset investment (taxed on your gains, which money doesn't have).
That is the definition of a bubble. If people buy Tesla because they think others want to buy Tesla stocks rather than thinking the company will do well, then Tesla stocks are in a bubble. The same thing applies to USD. It being a reserve currency means it can keep its value without having assets backing up that value, that is how we define a bubble. Of course bubbles can last a long while, which is probably what you mean, but it is still a bubble and it will pop at some point.
Another reserve currency right now are bitcoins. Bitcoins being used as a reserve currency means people buy it to keep the value high, so that their savings doesn't go to waste. I'd still argue that bitcoins are a bubble, like the USD.