system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why can't countries like Japan with so many zeroes in their currency just remove a few?

E.g. 1 dollar is around 100 yen or about 21,100 Vietnamese Dong. Do countries need that many digits?
gpt
Many countries, such as Turkey, have in fact done this. 

There are a couple of difficulties. First of all, there is a huge amount of financial data being processed by institutions like the government and, in japan, the nikkei index.

In addition, currencies usually don't climb to such face values purely by chance. They are there because of hyperinflation caused by economic problems. In Japan's case, i'm sure they're economy has stabilized to the point that they could institute redenomination if they wanted to, but they would probably say that the costs of reindexing the countries finances is not worth the benefit of simpler face values.