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