Music is no different than any other discipline. Except perhaps, like all the "arts", susceptible to subjective appreciation in the discernment of the unschooled and untrained layity. And, at times, (dear lawd) even schooled and trained peers. Go figure.
But, as with any discipline, there are definite hierarchical levels of pedagogy to be both accomplished and mastered. Given that, it is quite possible, in most circumstances, to discern ones level of "musicianship" and virtuosity. In short...either you got it...or you ain't. Amazing expertise and total suckatude being the two extremes of the scale. Like it or not...them's the facts, Jack.
Try going ahead and paying your plumber for fixing a leaky faucet by creating a spewing fountain of cascading water emanating from said faucet because "it satisfies his inner groove". And calling him a "genius" to boot.