Synchronization between IMU and images using Ros1

Thanks @Myzhar for your answer. Now, I have a few more doubts:

What happens when the synchronization between both sensors is disabled?
As far as I understand the IMU and image timestamps will be set to the host clock? Are these timestamps reliable? what i mean: is there any drift, offset or lag between the IMU and the camera timestamps?

For example, would the ZED 2 work with a tightly coupled visual-inertial odometry (such as ORB-SLAM3 or VINS-Fusion)?