Thanks for voicing your concern. Several applications out there (e.g. Mailtracker, Streak, etc.) provide tracking capabilities that include details on the recipient’s location, device, and number of opens. We at Pluto decided to only track the time that the email was first opened because we calculate some expiration times based on when the message was opened (e.g. email expires 1 hour after open). If we did not display this information, the user could always calculate it anyway from the email’s time of expiration.
David and I are both concerned about privacy, however, so we may implement an option to obscure tracking details in the future.