It doesn't matter (for the game) if USD gets inflation, what matters is to remain the world's first choice of reserve currency. As long as that is true, and as long as PED remains pegged at same untouched rate, it has no relevance how much inflation is there. Of course, as long as we're not on the bring of destruction as worldwide economic system, but let's not smoke illegals, because then whatever happens to Entropia would be my last concern, to be honest.
Then, it already happened in the past, in 2008-2009 and ingame was a bonanza. Wether it was well managed or not, that has to do more with the game systems themselves (high tt ul weapons, for example) than with the financial considerations about USD. But I can say it was great depositing against american rupee back then.
Your best bet is to always keep your money in what you know best. If you're good with stockmarkets, do that. If you're good with crypto, do that. If nothing applies, a savings account/a private pension in your national currency is a way better endeavour than to adventure in something which you don't really know and where you risk meeting a shark at every dot com. Especially trying to provision for a hiccup of a couple of years can be particularly tricky, is a much more volatile margin than over, say, 10 years.