What is the use of DEFAULT domain in a Domain separated instance?

[Suggy]

What is the use of DEFAULT domain in a Domain separated instance?

Doc says "The default domain is the domain to which the system automatically assigns task and user records that are not already assigned to a domain."

To test this, I ran below in script background from Global domain:

var gr=new GlideRecord('incident'); 
gr.initialize();
gr.insert();

I see that the record is getting created in GLOBAL domain, instead of creating in DEFAULT domain.

Am I missing anything?

If my understanding is wrong, tell me in which scenario a record gets created in DEFAULT domain (I need to test that).

Thanks!!!

[Adam43]

Should that default/OOTB domain be a sys_user_group reference value or a string value?  I'm dealing with issue where some of my users are in a group reference named "global" and others have a string value that reads 'global'.  In sub-instance where we use scheduled data imports to migrate our user data- I keep deleting the group version and it shows up again when data gets updated from Production down.  Though the Prod version of those users have the 'string' value version.