The downside is that it needs to trash nearly 32kB of RAM when the sector needs to be cleaned. So I'd probably do that in CHR-RAM, trashing the gfx in the process. So any program using this would have to be prepared to reload several (or all) of it's CHR-RAM banks. Flash devices with little RAM to ...
This is called "ateji" (当て字) and is basically a form of rebus used with kanji. The practice started from the view that it was necessary to have kanji equivalents of foreign loadwords (http://en.wikipedia.org/wiki/Japanese_words_of_Portuguese_origin) I guess its used for the same reason you...