I'm not catching you on any word, I'm looking at the dictionary definition and silly claims that people who quite obviously "put (money) to use, by purchase or expenditure, in something offering potential profitable returns, as interest, income, or appreciation in value" are not investors. That's nonsensical.
I live in a country with high inflation. People buy a lot of USD to save their money. Are they investors?
IMO, as a matter of common English usage, if purchased to hold for any meaningful period of time, yes. It certainly offers potential profitable returns [from] appreciation of value. I've certainly heard people talk about "investing" in various (fiat) currencies. Such usage is quite common.
Legally, ask your lawyer, don't ask me, or anyone on a forum.