Its easy for a passerby to appreciate the work, skill, and creativity that goes into a painting or song. Its hard for the average person to infer those things looking at an electrical box or a plumbing network. An electrician knows when they're looking at good up to code wiring and a plumber can tell if the plumbing can be put together right. Those are things the average person has no concept of and doesn't want to think about all unless they have to. One provides instant artistic appeal while having no practical value, the other provides practical value but its systems are too complicated for the average person to appreciate in totality.