This setting is needed to set the time zone by EET, Eastern European Time, by geolocation of registered numbers.
If you have it turned off, the software automatically sets them according to the geolocation of the phone number to be registered.
If you want to experiment, then you need to first of all figure out what time zone you need, how to set it correctly, so that there will be no mass bans because of the obvious difference between the geolocation of the account and its time zone.
Please note that the time zone is set according to the EET format. This is important!