I think the main charactaristic to look for when discerning the usefullness (good &/or BAD merits) of what and how one is practicing is that as you are practicing thingy "x", there should be a discernable waning that as you are practicing "x" senses that you are needing to pay less and less attention while playing thing "x", in order for you to continue to be doing it a manner that is consistent with what you wanted it to be like/sound like.
N.B, I did not say---> in a manner that is consistent with the "correct way" of playing thing x...My particular belief is that when talking about any aspect of one's music (maybe its the harmonic aspects of one's thoughts, maybe its one's timing, could be about any part of what one is doing during life that is of a musical nature) that to speak of it/ consider it/judge it...for that matter ANY OF IT with a dichotomy of "correct/incorrect" is not only unhelpful but is itself unhealthy...instead of "correct" or "incorrect". Instead, there is only "what you want to do" (or had wanted, if what you where wanting was in the past tense) and "what you actually are doing" (or had been doing, if what you are considering/judging has already transpired/come to fruition) .