With the caveat that too much noise and commotion detracts from the Eucharist (as I noted in the message above).
I do think however that there are some absolute standards in music (as there are in just about anything.) Music that is poorly written, poorly composed, or poorly performed is not our best effort to give to God.
To respond to your analogy, of course I would love my child's song of praise no matter what instrument it was performed on or how well (hey, I listened to some pretty dreadful stuff while my daughter was learning to play the violin!) And I'm sure that God loves and appreciates our praise although the best music on earth cannot compare to the perfect music of the heavenly choirs.
But although I love my children, I would be disappointed if they did not put forth their best effort but just went through the motions.
Comfort is good as far as it goes, but I personally don't want "comfort" in church music -- I want something that takes me out of myself. A Talis canon, properly done, is truly awe-inspiring. Our choirs have done some anthems that have brought me to tears.
One of the Godliest moments of my life was when our kids' choir performed selections from Mendelsohn's Elijah. And on that note: having seen a group of 2nd-6th graders put those very difficult pieces together from scratch in a week of choir camp, and still be singing it from memory months later, makes me want to injure those kid choir directors who waste the kids' talents on insipid crap. Our choir director has found that the higher he raises the bar, the better the kids like it. (He's exceptional, obviously....)
Some guitar band repeating the same phrase over and over cannot compare. Then again, the composers can't compare to the masters, either....