[Not a question] Importance of sql server agent

TechNet:

SQL Server Agent is a Microsoft Windows service that executes scheduled administrative tasks, which are called jobs in SQL Server 2012.

SQL Server Agent uses SQL Server to store job information. Jobs contain one or more job steps. Each step contains its own task, for example, backing up a database.

SQL Server Agent can run a job on a schedule, in response to a specific event, or on demand. For example, if you want to back up all the company servers every weekday after hours, you can automate this task. Schedule the backup to run after 22:00 Monday through Friday; if the backup encounters a problem, SQL Server Agent can record the event and notify you.

WikiPedia:

SQL Server Agent is a component of Microsoft SQL Server which schedules jobs and handles other automated tasks. It runs as a Windows service so can start automatically when the system boots or it can be started manually. It is .

Typical system tasks performed include scheduling maintenance plans (such as backups), handling Reporting Services subscriptions and performing log shipping sub-tasks (backup, copy, restore & check). User tasks, such as scheduling some T-SQL or command line statement are also common.

SQLAgent has support for operators and alerts, so that administrators can be notified, e.g. by email.

Oreally:

If you'd like to automate some of your SQL server tasks, check out SQL Server Agent. With it you can schedule jobs, restart services, send email alerts, and perform other automation.