Hey There @SeanH060 !
This is a great question, as of right now our poll block does not have the option to have a comment box such as you described above. However that's a really great idea and i'd love to share that with our team!
The feature you're describing is something right now only our survey tool holds. You'll want to follow these steps on How to Create a Survey. using this tool you can create your same poll with an option to have "Other" Allowing them to comment anything additional or you can include a comment box!
Once you've created your survey and are satisfied, you'll want to publish the survey. This will allow the responses to be recorded.To replace the poll block in your email campaign with this newly created survey, you'll want to locate the survey's URL which you can find here.
Once you've got that survey URL I would advise to use our button feature under the build menu. You can link the button up to that survey you created. This allows those to click on the button, get to the survey and have the option to comment if needed.
Again, this is a great question. Let us know if any further clarification is needed, we're always happy to help!