The human voice, at its best, is able to sing three octaves. It can also sing very softly and very loudly. It can project ranges of emotion that we can't even use words to describe.
Our normal speaking range, as reflected by an auto-tune device, spans less than an octave. Most speaking voices seem to only ascend a fifth above the "tonic" that is our baseline speaking voice. We rarely ever go below it in normal speech, unless we are doing so deliberately. Music generated by auto-tuning is therefore extremely restrictive. It seems always to be harmonized tonally, and it always seems to be accompanied by a steady rhythm, making patterns of speech have an elevated rhythmic interest in comparison with the background. Auto-tuned music also seems to come in a very small variety of dynamics. Auto-tuning, unlike sprechstimme or recitative, isn't generated by people. It's generated by machine.
Some people love it.
I find the practice of auto-tuning interesting, but only to a point. It is so easy to slip into the practice of being dulled by music, and forget about the enormous potential we have to embrace the full naturally-generated musical spectrum, with all its ranges, voices, and possibilities, and be stimulated by it.