It's still an important piece of information, first because it disagrees with what we previously thought, second because there are fringe cases in which learning a language doesn't open you to anything else.

I'm Spanish and live in the Basque Country. Everybody speaks Spanish here, but we are supposed to also speak Basque. The idea that it's advantageous to learning and such is one of the main arguments used to justify a push to learn the language. Basque language was the subject I invested the most time in through my whole compulsory education, so frankly, I do care.