Correct. It allows you to either edit or delete (or both, in which case it first edits, then deletes) all your comments, but it also allows you to filter by subreddit or date, and it even gives you the option to back up everything locally, so you don't lose everything like saved posts or something.

https://github.com/j0be/PowerDeleteSuite

At the bottom, drag the big green button to your bookmark bar, then open your profile page and click the bookmark. It'll give you all the options. :)