transliteration involves a good understanding of english alphabets and qwetry. Many people in india don't have that. Only people who regularly type using transliteration are those who are familiar in english
Also hindi language search is lacking many features which is taken for granted. Situation for other language are even worse
Look at the result for two same search in english and bengali https://www.google.co.in/search?q=delhi+to+calcutta https://www.google.co.in/search?q=%E0%A6%A6%E0%A6%BF%E0%A6%B...