Control Center Authorized Devices not unique and repeats for each login

I've been trying to understand the devices listed in the Control Center's Authorized Devices. I've been told that each time a login occurs on a device (phone, laptop, tablet, etc.), an entry is made as one of the authorized devices. Supposedly, each device is unique but they are NOT. Instead, the authorized devices are simply a log entry of whenever a login occurs using your account on a device. No way to identify the device, so the owner has no clue to know if a hacker has penetrated your account and logs in using your account. I had hopes that this would help identify security violations, but it only confuses.If the authorized devices is going to be a login log, please add date/timestamp and geographic location.