They are
incredible compared to "no labs at all" and "no way to run experiments" as the above poster lamented.
Mudflation aka hyperinflation aka situations where "the money printer goes brr too fast" have happened in the real world. Sometimes at "extremely" small scale (for macroeconomics) such as company town scrip, but they've happened and affected real people's lives.
But also, if Bitcoin is real then videogame economies are very real. You can trade USD for most in-game currencies. Sometimes directly in game as micro-transactions today ("diamond" or "platinum" middle funging currencies that convert to other game currencies), sometimes on trading platforms that are certainly against game terms of service and possibly illegal in some states, but that doesn't really stop them existing or people living in low wage countries making ends meet by grinding game currencies to sell for "realer" ones.
(Mudflation is also the answer to the why the book I read of "Ready Player One" was better than the one the author wrote because it seemed obvious the economy in the book was a textbook mudflationary one and much of the dystopia outside of its central game could easily be explained by how much of its economy was tied into its in game mudflationary currency. I appreciated that Hank Green's book "A Beautifully Foolish Endeavor" did a better job of doing that on purpose.)
> They are toy universes.
So are most experiments, fundamentally. You model the real world as best you can. You do what you can to eliminate variables. You learn from your experiment and you improve your model. You can't test the entire universe all at once, that's too many variables, you find the interesting toys that seem to look enough like our current understanding of our universe and then you play them until you break them (assert either the null hypothesis or the alternative hypothesis). Repeat until done.
Your examples seem easy to build toy universes for. The Animal Crossing series has decades of "research" in the effects of raising a central bank interest rate. (Look for Tom Nook memes, they alone are a modern study of macroeconomics and teenagers' direct relationships with them.) Many MMOs have "trades" and "crafts" that need to balance a minimum wage to get players interested and/or invested in them versus opportunity costs in other systems in the game. Funding Education is a similar problem explored in various RPG mechanics by sometimes direct analogies such as investments into player attributes and skill levels and skill trees.
And so on and so forth. The boundary between "real" and "virtual" economics seems nearly nonexistent, they are the same thing (and currency always wants to flow between them). In this case the map seems to be the territory. In this case the analogy seems to be the real thing. Because people are involved and people are ultimately irrational, but start to do really interesting economic things the more people you put in the same "place", whether virtual or real. Which is what macroeconomics has always been about.