Maybe, but 210,000 yen is roughly $1,400 dollars. That is probably a month's rent for Kobayashi.Consider how long Kanna would have kept one of those seemingly pricey chests. The money would have been well spent. The card-stock chest is likely to crumble-away in a few decades or perhaps centuries even when treated with very great care.
For the relevant comparison, you should do the computation in terms of purchasing-power parity, rather than in terms of exchange rates. And that means that ¥210,000 is more like US$2,135 — about 50% more than you calculated.Maybe, but 210,000 yen is roughly $1,400 dollars. That is probably a month's rent for Kobayashi.
dragons have magic, so maybe they can just reinforce the card-stock chest with magic to make it super durable for agesThe card-stock chest is likely to crumble-away in a few decades or perhaps centuries even when treated with very great care.