Component Specific Versions is one of the main functionalities of the add-on and one of JIRA's the top voted feature requests. The add-on allows you to define which versions are valid for which components. While doing this, the add-on has minimal impact on your JIRA. It doesn't invent new fields. You define versions and components of the project as usual and later you map which versions are valid for which components.
The add-on is highly configurable. There are some corner cases like handing multiple component selection on the issue, relationship with bundles, handling of affect versions etc. We strongly suggest you to go over each configuration option carefully before using the add-on.