When I'm in the US, I very seldom use cash. Card or a payment app...

In Japan, which has a much more cash-oriented economy at the retail level, there's no "sub-currency." That is, the yen doesn't break down further (it doesn't need to: it's only worth about .62 of a cent right now). Accumulating a big, inconvenient hoard of 1-yen coins is a constant irritation. These days lot more Japanese businesses accept electronic payments (apps or IC payment cards like Suica or Pasmo, mostly...sometimes but NOT always regular credit cards), but a lot of small shops are still cash only.

Interestingly, most stuff is priced at pretty even yen amounts (that is, the price will end in one or two zeroes). The odd amounts result from tax, which is why the one yen coin is still ubiquitous..