seeing someone else's work does not mean you really understand it. We've all seen Michelangelo's David, but none of us could recreate it. Just because you've seen the wiring/conduit in the wall does not mean you know the hows/whys about it.

Yes, but a person who has visited hundreds of art museums will have a better understanding of art than a guy who only paints landscapes or carves wooden figurines. You can learn a lot by observing what is good work and why, even if you didn’t produce it yourself.

you are giving the word "understand" too much depth here. it's pretty obvious what the parent post was getting at.