What the others said - tummy time is meant to replace something babies would already be getting through being carried in arms.
My first baby had the most tummy time, because we were late to babywearing and I kept trying to persuade her to be put down. She crawled latest of any of mine (nine months). My second had a fair bit of time on the floor, because she was very colicky and liked the pressure on her stomach, so she would sometimes cry in arms (even in colic-relieving positions) until I laid her down. She was my earliest crawler. My other two were rarely put down, and crawled at six and five months respectively. All of mine so far have walked between nine and twelve months, all being carried almost exclusively at the point they started walking (seems to correspond with a period of increased stranger anxiety in my babies).
So from my four, I see no relationship between time being held and confidence in propelling themselves. It’s not as if they *never* touch the ground by the time they’re nine months or so. xxx