Ancient Egyptians didn't use precious metals. They used something far more mundane. You are a farmer? You bring your harvest of corn to a storage house and receive a receipt of your deposit on a clay tablet.
But here is the thing. Storing grains is expensive and they don't last forever, so the depositors are charged the cost of storage if they keep their receipts for longer than a year.
Now imagine you do the same thing except your receipt is gold. The concept of an eternally lasting receipt should raise an eyebrow. Who is going to pay for the storage costs? If nobody, then congratulations you just invented a Ponzi scheme! Early depositors get bailed out by future depositors!
Alternatively, the value of the coins must shrink to accommodate the loss of grains, but here is the thing. You are in a deflationary boom, you don't care about reality. But at some point you will try to spend your deflated money, right? Well, you will come crashing down to reality. The sudden price adjustment towards reality will cause a lot of inflation all at once.
Ok, so now that we know the dynamics of precious metal money even in the absence of government intervention, aka cycles of booms and busts.
We can now think about the motivation of the Roman Empire which is the most famous historic example of "debasement" because they were the first ones to do it on a large scale. Well, you see, the Roman empire was constantly expanding its borders to acquire new precious metal mines. This works until you run out of mines. In other words, it was a pyramid scheme that needs a constantly expanding territory.
So instead of thinking as precious metal money to be something aspirational, it would be smarter to realize that it doesn't work. I mean the easiest way to prove the idiocy of a gold standard is to point at all the fiat currencies that originated from a failed gold standard, which is basically all of them. In other words, fiat currencies aren't some kind of perversion of money, they are the late stage of a failed precious metal currency! It is easy to see why. Precious metal currencies don't circulate fast enough to clear the market because of their deflationary tendencies aka hoarding. So banks create a money substitute that is as good as the real thing but the problem is that the substitute can be hoarded as well so the problem can never be solved other than by substituting existing money with even more of the same hoardable money. In other words, the money supply has to rise all the time to accommodate uncoordinated/speculative saving decisions that have not been properly communicated to the market.
What I think is either sad or amusing, is that people think that these dynamics can somehow be avoided just by the government being tough enough on the economy to make all forms of money substitutes illegal, as if that wasn't some kind of massively disruptive government intervention.
Now let's go back to Ancient Egypt. If people hoarded the grain money, then the same dynamic would apply to that money right? The grain banks would have to create fake deposits for grains that don't exist and there would be constant runs on the banks, right? Except there is no historical evidence that this ever happened because people didn't want to pay the storage fee. Isn't it strange that this ancient civilization never recovered, even after thousands of years of Roman currency? Maybe the whole idea was a scam from the start. Permanence in our world is a meaningless concept. Your gold money will remain on earth billions of years after humanity has gone extinct, how exactly is it supposed to maintain its value?