Being a multilingual is a prideful thing. The effort to learn a new language is daunting. Just imagine the sheer numbers of vocabularies each language has.
One shall not learn a new language just for prestige. If you don't use it, you will eventually lose it.
If you want to add a new language into your linguistic repertoire, make sure you really love it or (will) use that language, otherwise you risk having it decimated when you stop learning.