Enhancing Email Re-Engagement: Tips for Freebies and Polls

We are initiating an email re-engagement automation. In writing the email, we are going to offer them something as a freebie. Is there any value in having them reply to this email? Does it provide anything other than showing engagement? Or does it help google trust us more in showing up in their inboxes? We are doing short poll within the email as well. Any advice? Also - is there an automated way we can deliver the freebie when they reply to us? Feeling like this might be opening a can of worms if we have to manually manage all of it.