For us this would also be an important feature. Like @acaringi we have also designed some of our emails in order to trigger a reply as the preferred action. Now we can’t measure this in Hubspot. I have to ask the owners (the sender is dynamically set to the contact’s owner) how many replies they received in a specific time period, in order to analyze the effectiveness of the email campaign. That is a hassle and could be easier.
Idea: add an optional toggle to track replies on email campaigns. This would set a specific reply-to address that looks very much the same as the sender’s email address. Once this reply-to address receives the email a reply is measured and the email is forwarded to the actual email address.
For example
Sender: martin.johnson@company.com
Reply-to: martin.johnson@company.hs.com (or martin.johnson@email.company.com > if that’s a domain set up with hubspot).
In any case, I would not want to have to rely on the Gmail inbox integration. If the owner hasn’t set that up or disables it, the data might get skewed.