Any search, table, or chart that you create can be saved and made to appear in the menus for other users to see. With that power, why would you bother creating a dashboard?
Here are a few reasons:
A dashboard can contain multiple panels, each running a different query.
Every dashboard has a unique URL, which is easy to share.
Dashboards are more customizable than an individual query.
The search bar is removed, making it less intimidating to many users.
Forms allow you to present the user with a custom search interface that only requires specific values.
Dashboards look great. Many organizations place dashboards on projectors and monitors for at-a-glance information about their environment.
Dashboards can be scheduled for PDF delivery by e-mail. This feature is not the most robust, but with some consideration, it can be used effectively. With all of this said, if a saved search is working the way it is, there is no strong reason to turn it into a dashboard.