Maturecasfan
I believe the idea of the dive is to prevent the ball being dropped or knocked out when attempting to place it on the ground. It's relatively easy to suffer either fate.
Furthermore, we love it when a winger dives to avoid the defender. Looks spectacular and increases the change of scoring now they've removed the 'in touch' rule when colliding with the corner flag.
Either way, he had acres of space to dive into so there's no excuse.