Is Azure Functions over Web API Beneficial?

function.json

// function.json
{
  "disabled": false,
  "bindings": [
    {
      "authLevel": "function",
      "name": "req",
      "type": "httpTrigger",
      "direction": "in",
      "route": "products/{productId}", // Route template
      "methods": [ "get" ] // HTTP verbs
    },
    {
      "name": "res",
      "type": "http",
      "direction": "out"
    }
  ]
}