Some years ago I went with a friend (who was a much more experienced musician than myself) to hear a jazz group playing at a club. After the show my friend asked what I thought of the guitar playing. I commented with something to the effect of, "It was hard for me to get into it because of the guitar tone." He responded with, "Oh I see, you're still hung up on that." This comment had some staying power, in part because I looked to this friend as a teacher. No doubt his comment provoked my insecurity; it also challenged my core musical values. There is so much to say about insecurity in music, but for now I'll just acknowledge that self-esteem involves how we perceive ourselves in relation to real or imagined standards of accomplishment. Self-confidence can be so finicky. In terms of core musical values, I realize now that other layers were at work in the difference of our perceptions of the mid-rangey guitar that evening.
Tone in music is hugely important. I don't know if it is more or less important than the notes or rhythms played but I know for sure that there is no such thing as being "hung up" on tone. Many players of acoustic instruments might immediately agree with this statement. When electronics or mechanical filters get involved, however, it can be harder to assess tone quality. Things become more subjective (uh oh) so we're less sure of how to evaluate relative mastery. Maybe this is part of how conventions of tone for electric instruments develop within a given musical style. A particular tone has worked historically, so just plug in and use it so that we can get to the "real music."
I don't discredit that comfort and taste develop around history and nostalgia - sometimes we love a particular sound if it references a lineage or a personal or cultural memory. Or maybe musicians often assume that unconventional tone choices will get in the way or distract listeners. But I wonder if some bias against tone as a musical component worthy of serious pursuit by default (as with harmony, for example) also has to do with the fact that it's tough to evaluate. We react to tonal quality emotionally and physically, but it's hard to gauge intellectually. The standards of excellence are murky. This spells bad news for certain ways of thinking.