His point was that Bitcoin shouldn’t be an investment if it is to be used as a medium of exchange wasn’t it? As long as there has been money people have been trading and speculating on it in order to make more.
Also it certainly isn’t a problem if the price of Bitcoin steadily “inflates” in relation to the dollar as long as its value is truly reflected in that price.
Currency traders of course gamble on the fluctuation between the values of different currencies based on the emotional evaluation of how each country is handling their affairs, the relative trade balances, and a lot of pushing around by wealthy traders.
But when a currency changes value within it’s own country by large amounts, it is generally because it is becoming worthless as a currency, and people are bailing.
Because for most people, it really doesn’t matter much whether a dollar can buy 80 yen, or 120 yen. But if they walk into the grocery store and the milk that was $3 yesterday is $5 today, and then it’s $4 tomorrow, that is a real problem.
Because the point of “currency” is to allow someone to exchange a unit of work now, for a unit of consumption LATER. If currency can’t do that, because the units keep changing, you will end up with a barter economy.