What do Apple Diagnostics for Mac offer better than Apple Service Providers' tests? [closed]

Apple's embedded tests for Macs seem very shallow compared to those used by Apple Service Providers (AST2 tests).

I know AST2 tests are very good at catching sensor failures (such as temperature, voltage and current sensors), are the embedded tests as capable?

I wonder if these tests are programmed in a hidden partition, in the firmware or they're downloaded from the cloud.

One of your wonderments is where the tests are actually stored. They're not in a hidden partition nor downloaded from the cloud, they're located in the firmware on the main board.

The included, automatic tests are not as comprehensive as those that can be performed by Apple Service Providers.