There is a check box in the settings that can hide Captcha from Admins and registered users making it easier for them to work with comments on your site.
Want to add comments to your post? On the upper right of your post edit area, click on "screen options" - select discussion and comments.
Make sure you installed your Captcha key so you don't receive so much spam from your comments form.
Any other tips you'd like to add about Captcha and Comments?