Today, 11 Iyar, is the yahrzeit of Reb Naftali Tzvi of Ropshitz. He used to speak about the great yichus he had from both sides of his family. He said over the following about the benefits of yichus:
Take a person who's a real tzadik, a great scholar and serves Hashem in every way. He gets up at midnight and cries over the churban for hours, then he immerses himself in the mikva and spends the rest of the night delving into the hidden and revealed parts of Torah. Come daybreak, he goes to shul and davens for hours. After davening he sits and learns more Torah. Finally, close to midday he sits down to eat and gives a heavy sigh and says "am I really serving Hashem with all my ability?" Now, if he comes from simple stock he says "compared to my Father I'm not too bad". However, if his ancestors were great tzadikim he will think of his accomplishments as meager and say "when will I reach the level of my ancestors?"
That says the Ropshitzer is the value of yichus. I believe the reason why he named his sefer Zera Kodesh was because of the great yichus he had, which he used to continuously work on himself, making him into the towering figure that he was. He is still vey much alive through his holy sefer, Zera Kodesh.
See Heichal HaNegina for more on the Ropshitzer.