One-Way Valve Glass Coffee Storage Jar

The jars are good, the lids too. Only in the description it says there's a one-way valve for releasing expanding gases. The valve, if you can call it that, is there. Only it lets air through in both directions. So what the hell is it for? Guys, Chinese people, when will you finally start making everything with quality, aren't you ashamed? It seems like you're already flying to the moon, but you're still the same shoddy manufacturers you always were.