Also, the escope of this project is much more important for the
projects on these languages, and for speakers of these languages, rather
than the English Wikipedia or its readers.
I partially disagree. Certainly it is very important from the perspective of
providing material about the native countries of those languages.
However translating that material into other languages is also important;
the aim is to preserve as much knowledge as possible in a broad spectrum of
languages. The "elephant in the room" is that English Wikipedia is by far
the biggest and most well known. Followed closely by some of the European
languages. Translating the material to English/German/French gives it the
maximum accessibility - in terms of enabling* it to be used on the largest
Wikipedias and improving the chances that other language Wikipedias being
able to parse/translate/understand the material.
English is the lingua franca of Wikipedia (whether this is wholly a good
thing or not is a much wider debate), so providing accessibility in English
helps ensure important content like this reaches as far as possible.
* note that by "enabling" I don't mean "making it acceptable to
language source should be acceptable! Rather I mean "providing it in a
language that en.wiki editors will be able to make use of".