"Hello" and "habari" are equivalent greetings. "Hello" has no other meaning and although it doesn't matter here the word "habari" also means "news". In both languages we need not worry about precise meanings of informal greetings. In English we don't think about real meanings of "hi", "hiya", "hey", etc. In both languages there are meaningful greetings for formal occasions and in all cases the important thing is to appear pleased to meet someone, irrespective of the words used.