Do you think people buy stuff because their currency is steadily losing value, or might it be because they need or want stuff?
> When there is high inflation people will spend all their money as soon as possible, before it loses value. Too much inflation is bad too, but some inflation is good.
Your average Joe off the street has no clue about what inflation means or what the current official (understated) rate is. You're talking about a situation where it's obvious to everyone that they just should not hold on to the currency they have. Think hyperinflation.
> With the gold standard the supply of money is completely independent of the need for money.
The need for money? Well, if gold is money, then you don't "need money" because you already have it. There's no need to worry about your money having lots of purchasing power either, that's just a good thing.
> The discovery of a great source of gold will bring inflation;
And conjuring up trillions of quatloos out of thin air will not?
You're saying that the money supply increasing without a corresponding increase in economic activity will cause your currency's purchasing power to dwindle? Well yeah, that's about right. But what exactly is supposed to be the problem you're talking about here?
> an expansion of the economy without a corresponding increase of the money supply will bring deflation.
Yyyep. Again, what's the problem?
> The same would be true with bitcoin and bitcoin mining.
Ditto.