Creating a Web Shell on the server provides an attacker with persistent, disguised access, often through an innocuous-looking file that does not arouse suspicion. This access can be used by the attacker to navigate the file system, manage files, and execute commands. A reverse shell would not offer persistence; it only allows for a one-time session establishment which would be terminated once the connection is closed. Changing server passwords would increase the risk of detection, and scheduled tasks or cron jobs may be viable for persistence but are not as stealthy and can be easily detected by an administrator.