The reason bloggers leave that gap is so that they don't get polish all over their cuticles. That way they don't have to clean up around their nails, and they can keep the polish remover off of their skin so that they don't get terribly dry hands. It also is quicker to remove if it doesn't cover the entire nail, which is important when you're swatching 10 colors at a time.
When they do real manicures their polish goes all the way to the edges of their nails.