In various languages, the primary (preferred) quotation mark is different and "" isn't correct. Multilingual-oriented editors like Microsoft Word, Google Docs (Open Office too, I bet) allow to set a default pair of quotation marks, depending on language.
Now, when a user wants to type a quotation mark, he/she gets English "" and it takes a while for him/her to realise that the other options may be available on special character list. This situation requires him/her to stop typing, click on the Omega and find the right character. Therefore, VE may be considered as maladjusted to non-English users, even if there's the wanted character on "often used" list.
This should also work outside the content area, e.g. in the find and replace menu. Now, if all "" are to be replaced with e.g. «» (it's a frequent WikiGnome task *), user has to find «» on the special character list (which doesn't work simultaneously with find and replace), place it temporarily somewhere, open find and replace menu, type [space]", copy and paste [space]«, next repeat with " and ». Sounds kinda crazy, doesn't it?
// * To be clear, the problem with "" doesn't affect only WikiGnomes, who are mainly bold, experienced users, but all users, including newbies, who are forced to stop typing and find the proper marks.