This project specifically is probably not useful for others just because it is written in another language (unless it were to succeed in fixing problems or improving security or performance.) Redis is a server application, not a library, so there's a clearly defined and interoperable protocol to bridge the Redis server to other languages already. Writing a Redis client for the other language would be more useful.
More generally, as coldtea mentions, making integration into the rest of the language's ecosystem is the primary benefit of rewriting in another language.
The value of such a port to others depends on how easy it is to integrate between the two languages, either via libraries or other methods. The harder it is to integrate the two (and the absence of automated translation tools) increases the value of the rewrite to others.
Your Core-NLP example is actually an interesting one, because that library has already been ported to other languages... It is available for the C#/F# ecosystem (http://sergey-tihon.github.io/Stanford.NLP.NET/).
Comments
This project specifically is probably not useful for others just because it is written in another language (unless it were to succeed in fixing problems or improving security or performance.) Redis is a server application, not a library, so there's a clearly defined and interoperable protocol to bridge the Redis server to other languages already. Writing a Redis client for the other language would be more useful.
More generally, as coldtea mentions, making integration into the rest of the language's ecosystem is the primary benefit of rewriting in another language.
The value of such a port to others depends on how easy it is to integrate between the two languages, either via libraries or other methods. The harder it is to integrate the two (and the absence of automated translation tools) increases the value of the rewrite to others.
Your Core-NLP example is actually an interesting one, because that library has already been ported to other languages... It is available for the C#/F# ecosystem (http://sergey-tihon.github.io/Stanford.NLP.NET/).