Dialogs are a type of process in CRM where you can guide a user through a specific set of steps in order to gather information from them. They are similar to workflows in that you can build if-then statements and create/update CRM records. Learn more here.
If you've ever worked with dialogs, you may know that there is a comments section on the form by default. There is no way to remove it (that I know of). Anything added to this box can not be retrieved and used later without writing a plugin so as an administrator, we don't want users to enter anything in this box.
And as a user, this might be very confusing.. They see "Click to add
comments" and naturally assume that this is where they can add
additional information about the record they're working on. Unfortunately, that's not the case so I would suggest including a note to inform the user.