Agreed.
There is great value in knowing which things we (i.e. humanity and the scientific community) understand and which we don't. To me this is the primary message and the joy of reading/listening to Feynman. Over and over again he sketches out what we understand in a field and then highlights the questions that remain, and shares his enthusiasm and wonder for those unanswered questions that are waiting out there for a sharp mind grasp. This focus on the unanswered question is what makes his work so inspirational. It makes you want to become a physicist so you can go out and solve some of those mysteries. And that also is what differentiates Feynman's approach from how science is taught in most places. It's taught with a focus on what we know, which unintentionally gives the student the impression that we mostly understand things, which is completely wrong.
On another note, as a computer scientist and architect of large systems, it is important for me to know what is do-able and what is not, which problems we have solutions for, which are intractable nonstarters, and which we have a chance to solve in the right situation with the right brainpower applied. The details of why are less important. For example, I don't need to understand deep crypto to know what we can encrypt the comms between these two components. I know it's a solved problem, what it can and cannot do, and that's all that matters to me. Put it in my toolbox along with sorting, hash tables, full-text indexing, AJAX, machine learning, and hundreds of other techniques, each of which is its own deep field, and I can use this knowledge to design systems with high confidence that they are going to work as planned.