Central provisioning is the difference between a phone rollout that takes a week and one that takes a quarter.
Zero-touch provisioning means a device configures itself against your settings the first time it reaches the network. No per-device setup, no site visit to change a dial plan, no drift between locations.
The work is front-loaded: templates, firmware policy and network readiness have to be right before the first box is opened. Get that right and the rollout itself becomes logistics rather than engineering.