Hi,
There is another reason to differentiate capitalized words.
I think that the first useful use of Wiktionary is to learn a foreign language, especially for a beginner. You don't need a complete dictionary for that, you just need the most common words, which you already have in English, or will have soon in other languages.
If I use Wiktionary to learn English, I need to know that the language of England is spelled [[English]] and not [[english]], and that the fist month of the year is written [[January]] and not [[january]]. The same situation occurs in any language which uses capitals (English, German, French, etc.). In German, a cat is spelled [[Katze]] and not [[katze]], and in French, [[chat]] and not [[Chat]].
Regards, Yann