I can't read ancient Chinese, so in the case of the Dao De Jing, I'd prefer a translation, but almost all the books at Standard Ebooks were originally written in Modern English. I consider the original spelling an important part of the work.

Consider this edit:

https://github.com/standardebooks/h-p-lovecraft_short-fictio...

This is a character who would know that "'phone" is short for "telephone", but it's changed so that he says "phone". It ruins the effect of telephones being new and modern technology, and makes them so commonplace that people are no longer consciously aware that the word "phone" is an abbreviation. (Although it actually does need an edit, because the automatic conversion of the ' failed and turned it into a ‘ instead of the correct ’.)