The issue I have with 'ghoti' is that it doesn't make the sense they claim it to. The digraph <gh>, for instance, is never /f/ at the beginning of words, so it'd make no sense for it to be /f/ here. These graphs only have their set sounds in certain places in the words, and they can't be divorced from that. It's precisely why nobody would say 'fish' as 'ghoti'.
It's clearly a joke at the English spelling expense. Why does gh in the first place pronounce /f/ at the end of a word?
English is my second language. At first I found English quite easy: non-gendered nouns, simpler tenses, etc. But, after 25 years of using it it still shocks me at times. If you see a word for the first time you can have a guess how to pronounce it, but you could never be certain without consulting a dictionary.