Registered Email™ certified e-delivery services track delivery and message opening regardless of recipient or system settings and provide an audit trail forensic record that can authenticate content and uniform timestamps.
By contrast, some Gmail third-party apps provide basic email open tracking and provide simple read receipts or open indications. But they work only if the recipient has the right settings on and chooses to display images in their received email content. Even if it returns a read receipt or open indication, (a) the receipt or indication tells nothing about message content received, (b) times are based on the sender’s computer and are not uniform, and (c) format is simple text such that it can be modified and is not an authenticatable record.
An email sent from Gmail or G-Suite as a Registered Email™ message returns a Registered Receipt™ email proof of delivery record for the sender, regardless of recipient actions, settings, or software.