The employer needs to know the complete address of the employee for a number of reasons. One is for payroll purposes. Setting up an account for a person requires him to provide his address. Another reason is that if something wrong happens, they would know where to locate him or his family. The company also needs an employees address so that they can be certain of his identity. And another reason would be for mailing of anything necessary purposes.
Another downside to using an employment agreement template is the potential for building inflexibility into your business. In particular, employment law changes may invalidate or make an existing agreement out of date. If you use the same job template for hundreds of employees and the law changes, you may need to go back and have them re-sign new contracts. This would not always benefit the company, though it is a small risk to take to get the significant legal protections afforded by even the simplest of contracts.