Yes, I mean, all the options are bad. So let’s start there :)
First, if your money supply is the actual asset (and not just backed by it) then it’s even worse, since fluctuations in overall supply of that asset can cause very large valuation changes of the money you own. E.g. if we find a silver deposit 4x bigger than all the silver we already have, then suddenly all the coins people are carrying around are worth 1/5 their previous value. So it makes the currency unattractive to hold. On the other hand, if you run out of coins then as your economy or even just population grows then everything has to get cheaper because there’s only the same amount of coins to buy more stuff. And that encourages hoarding. These two things together make for financial disaster because nothing can really be relied on. And, this wasn’t as much of a problem before countries like the UK industrialized, which led to population explosions across the major powers.
Then again after WW2, when globalized markets became a thing, we saw another wave of industrialization and accompanying population growth, to the point that even asset-backed paper currency became problematic. There’s just not enough gold on the planet to back every other economic output. There’s only about 400 million pounds of the stuff worldwide. Assuming you could even get ahold of it all, you could only use it to back about $200 billion. Between 1950 and 1971 global trade expanded by a trillion dollars. And the global population nearly doubled. And we couldn’t just say “gold is worth more now”. There were treaties in place that defined the price of gold as $35 per ounce (which led to countries like France to try and destabilize our currency by buying up a bunch of our gold, but that’s another story).
But in a fiat system by adopting the currency you add your economic output to the overall system and your currency stability is now tied up in that economic output, so—your output goes down, your people’s belief in your ability to pay also goes down. This works super well in a rapidly-growing economy. There’s always more! More money-printing, more economic output, more debt… but the problem with this is—what happens in a world where things stop growing all the time? We have a few small examples and they aren’t pretty (Greece, COVID, and coming soon—China).