Three thousand of a coin per night? Why are mangaka like this? Clearly it's only a cheap way of bringing the (Japanese) reader's familiarity with the yen and its denominations to the story, but why bother? Normal coins with reasonable worth were already presented for the chicken skewers. Now the writer has gone from easy writing, merely having to remember that a gold coin is worth a bag of cheaper coins and two chicken skewers, to much more difficult writing, now having to explain this third-way coin which exists as an abstraction of each other coin as a money-commodity, why its price is so vastly deflated, why the gold coin is even minted if such a convenient third-way coin even exists, and so on. But the writer will never provide this exposition! In the first place its the fault of the reader. Isekai is a cheap alternative to writing both a fantasy world and a literally-me protagonist (any one of us can die/be isekai'd at any moment IRL, the protagonist is our common demoninator as a just-some-guy who works, is maidenless, happens to strive for strength in his delusions/fantasies/literally-me characters of the manga he reads etc., and is familiar with video-games, and so on). Anyway, my schizo instinct is that the imposition of the yen as a retreat from truly indulging in fantasy is in fact a greater indulgence of a fantasy version of Japan (or first-world society generally) by the author, merely continuing from faux-obsession (It's presented as a novelty by the orc's comedic reaction, the same as "ironicly" believing or writing something on the internet; the writer [of the "ironic" expression, whether some idiot on twitter/discord/etc. or this mangaka] uses this irony as a shield for his beliefs from [even his own] sincere interpretation or reaction) with Japanese "bathing culture," and we will probably move next to the faux-obsession of the onigiri or other "Japanese cuisine." I think this is the ultimate delineation between garbage and art: the manga as an expression of the mangaka's anxieties in order to defend them (from a delusion of society) vs. their expression in order to open new avenues of critique (from oneself).
If Spice & Wolf was isekai then it still would have been good, both as garbage and as art, yet if Overlord just took place in an MMORPG world without any players then it wouldn't have been good as art, as the human character is present in Ainz for the best parts of the series.