Romanized text may well be input into the search box on Japanese-language wikis, when the user forgets to turn on kanji conversion, is lazy to not do it, or doesn't know the correct kanji spelling. The same story goes for hiragana.
For example, I'd wish to see "東京" https://ja.wikipedia.org/wiki/%E6%9D%B1%E4%BA%AC listed in the candidates when I enter "touk" (an incomplete transliteration of the full romanization of 東京/Tokyo: "toukyou") in the search box of Japanese Wikipedia.
Google supports this at least since 2009. (Bing and Amazon do, too.)
Two screen shots to highlight the feature are included in the post above.