Joseph, Yiddish only has worth for sentimental reasons. It brings back nice warm memories of the old country (which was far from pleasant, by the way). It also has a very colorful way of expressing certain concepts and descriptions of Jewish life. It does not have holiness. Look, I miss morse code in ham radio which is no longer required for a license. But as much as I love it, I would not call morse code holy.
Those who teach Yiddish today at the expense of having their children become fluent in the native language, cause a difficult cycle of poverty which brings much pain on many families.