This is an interesting story why he became wearing those fingers tapes :
Michael was always pointing. He had such long fingers that we called them “ET fingers.” He used them as he danced in a mirror (as dancers do) on a portable floor that traveled with him, studying how he could look the tallest, the leanest- statuesque and slimming.
Half of Michael’s dance steps took place in his hands. Because the gloves didn’t fit the theme of “Smooth Criminal,” Michael needed to develop another device to help navigate the audience’s eyes to the line he formed over his head and across his body with his hands as he danced. In early 1987, when Michael shot the “Smooth Criminal” short film, we decided to put white tape on his fingers to draw más light. Michael loved this idea, because while we were making it functional, he was adding a little fun.
The Mickey to his Rocky, I taped his fingers up. As I began work on the 4th finger, Michael stopped me.
“That’s too much. That’s too ordinary.”
So just the pointer, ring and pinkie fingers would be covered in white tape. That was strange-odd. Michael loved people asking, “Why?” And “Why those 3 fingers?”
Then, as Michael danced, he would unconsciously touch his un-taped thumb and middle finger together, and the world asked, “Why does he do that? Is it a signal? What does it mean?” Michael appreciated his fans’ propensities to question, notice and buscar for meaning in the things he did. When they wondered about the finger tape, he didn’t want them to be let down por a reason as mundane as making better use of light o giving the illusion of taller and broader appearance. However, what we discovered over the years of dressing Michael is that when tu don’t address a fashion pregunta head on, people will find a reason – any reason – to explain it. So urban legend became that Michael bit his fingernails, and the tape was meant to prevent him from partaking in the imaginary habit. Michael loved the idea that he could make people question, notice, and buscar for meaning.