> Being "Long" in the USD implies general stability of the currency

It does not. Many currencies aren't stable at all; people still take long and short positions on them, either as part of an explicit investment thesis, or just by, you know, having some paper currency in their wallet. People have been buying gold for centuries as a way of reducing their exposure to unstable currencies.

I would assume it doesn't need to be explicitly said, but just for safety's sake, let's be clear: A long (or short) position is a bet, and you can bet on unpredictable things. Nobody uses the terminology, but technically you're "long red" if you bet on red coming up next on a roulette wheel at Vegas.

Currently equity markets have been consumed with discussions of the "meme stocks". People have been going long on, eg, Gamestop, but the stock has been incredibly volatile, and there are no underlying economic factors that even begin to support the highs it's reached. Again, being long in a super volatile stock because it's funny, or because you're bored, or because you're trying to make a statement, or because you believe it is bouncing around randomly and you're trying to profit from this is still being long on the stock.

Being long is not a moral judgement, it just means you've got an exposure to the asset becoming more valuable. If you own a share in Gamestock, or a USD, or few satoshis, or a house, you're long those assets. It doesn't matter why you own them.

> which as you say has a number of factors... all of which are non-existent in bitcoin

That is also untrue; many factors have exact equivalents, such as evaluating competing currencies for differences in projected inflation or deflation, projected interest rates, projected uptake in usage in new markets, projected change in regulations. If you think DeFi will continue to grow, or that Ethereum's migration to Proof Of Stake will finally happen and be successful, that suggests a relative strengthening of of Ethereum versus Bitcoin. If you think that a pure Bitcoin ETF will be approved by the SEC and will be good for Bitcoin prices, that suggests a strengthening of Bitcoin versus other currencies. And of course, you can evaluate the so-called "shitcoins" to decide if you think they'll ever get a fraction of the adoption Bitcoin and Ethereum have, etc.

> What exactly are you thinking factors into the growth of the currency? Beyond say... hopes and dreams (aka gambling).

As above. Although let's be clear: All currency speculation is gambling. Exchange rates are volatile, unpredictable, and for major pairs, impossible to manipulate. You can (and so very, very many people have) come up with some thesis about why the USD/EUR rate is going to move in a specific direction, go long (and/or short) in the appropriate currency, and get run over, because the market doesn't care about your thesis. Even if you're right about the thesis! :)

> as there is a government and usually a central bank that controls production of that currency

And...?

> they are not just random numbers fluctuating randomly...

They might as well be. Given the closing price of the USD/EUR pair today, there's no amount of information I can give you about relative economic performance of the US versus the EU that will let you predict the closing price of the USD/EUR pair tomorrow. Or next week. Or next year.

> is there a fiat currency that shows as much volatility for as long as bitcoin has?

There are - and have been - some very volatile currencies. Certainly bitcoin is at the far end of the volatility distribution. What of it? Again, you seem to have the model that you can only bet on sure things, and the more random something is, the less you can truly "gamble" on it. That is, if anything, the opposite of how it works.