Serverless broadly refers to applications that circumvent the need for an always-on server component by using third-party hosted services to manage server-side logic and state.
The serverless model represents a significant shift even from the traditional cloud service model where customers had to reserve and pay for a predetermined amount of bandwidth or server space, irrespective of usage. It is therefore easy to see the value in a model that delivers on-demand execution, dynamic scaling based on application loads and pay-per-use pricing.
As a fully-managed service, serverless ensures that all infrastructure related issues are shifted from the developer to the vendor.
CHECK OUT THIS INFOGRAPHIC that identifies some key benefits of the serverless model.