when to use make olddefconfig

Hi, I was going through this link : https://kernelnewbies.org/OutreachyfirstpatchSetup , and came across the make olddefconfig cmd. The explanation on the web page is very confusing. Can anyone please explain in simpler way when "make olddefconfig" cmd is intended to be used ? The webpage says this : If you need to make any changes to your configuration, run this command to silently update any new configuration values to their default. -- Thanks and Regards, Sumit