What Levi may lack in singing chops he more than makes up for in pure charm and stage charisma, the kind of stuff that most of his contemporaries who may be able to sing the role flawlessly lack. He is a theatre showman in the style of Robert Preston. He is a revelation in SHE LOVES ME. He also is a perfect match to Benanti's bravura performance, which is a nearly impossible task. They complement each other beautifully and rightfully were recognized for the fireworks they achieve at Studio 54 eight times a week.
And regarding Groff, it wouldn't be shocking to see him win. Many people have won this category for brief roles. Groff milked every line, every gesture, and every movement for all it was worth and then some. It was a magnificent performance. I expect Diggs to win--and would vote for him--but a Groff win would be equally great.
"Some people can thrive and bloom living life in a living room, that's perfect for some people of one hundred and five. But I at least gotta try, when I think of all the sights that I gotta see, all the places I gotta play, all the things that I gotta be at"