[nilkn]

The argument usually hinges on simple counting: there are only 21 million possible bitcoins, and 21 million is nothing compared to the money supply of other currencies. Therefore, in the end (supposing bitcoin succeeds hugely), the exchange rate must be enormous.

So the difference between 1BTC and 0.1BTC is that there are significantly fewer of the former than the latter.

[sliverstorm]

There are only 21 million possible bitcoins, but there are 2.1e15 possible satoshis, which are the only denomination that really matter.

[nilkn]

I don't think you're following the argument at all. A bitcoin is composed of satoshis, and the price is additive. Switching units doesn't actually change the price.