I agree with you in the broad respect: rote memorization is not very impressive in terms of education. Teaching kids to memorize the dates of when the Aztecs ruled is pointless when we all have access to wikipedia in our pockets.

But I do think there is another, deeper sense in which having a "good" memory can aid in "penetration" as you see it. Having an impressive memory is not just about storing information but storing it in a way that encodes the information as as to be easy to recall in the right context. If you've read a lot of books and have retained the information in a way that makes you a good conversationalist because you can access the right facts in the right context, that is part of what it means to be educated and intelligent.