Good criticism can enhance the understanding of a performer. Sometimes the flaws
are as important as the good stuff.   For example, many songs about topical subjects have been written as well-meaning attempts to stir public consciousness. They have been performed by great singers and players. Many of these songs, however, are
hastily written, patched together in the heat of the moment and do not reflect some of the elements of great songwriting such as consistency in focus, revelation about human character, specificity where you "show rather than tell", rhyme schemes, stanzaic consistency and other factors.

When you bring these things to light, you improve the art of songwriting and you show
the separation between artist and the art. This is good criticism to me.

Sometimes a great performer will miss the context of a song. They get it wrong from the standpoint of meaning or historical background or just inappropriate phrasing and emphasis on the wrong words. Pointing this out to me in no way invalidates the
performer's essentially good qualities but sheds light on the performance in a constructive way.

One characteristic of this albeit kinda' crude is the nice singer-performer Stan Rogers
doing "Waltzing Matilda" as a waltz. He sang well, played well and missed the boat
on this song.

Frank Hamilton