Explanation
Working Location Enable Primary is a setting on the Working Territories work rule that defines whether resources should be matched with service appointments based on their primary territory only or any territory they belong to[186]. Match Territory is a work rule that defines whether resources should be matched with service appointments based on their territories[187]. Selecting Working Location Enable Primary on the Working Territories Work Rule and including the Match Territory Work Rule would allow Universal Containers' scheduling policy to look at both primary and secondary service territories by enabling matching resources with service appointments based on any territory they belong to and prioritizing matching resources with service appointments based on their territories. Removing the Match Territory Work Rule would not allow Universal Containers' scheduling policy to look at both primary and secondary service territories because it would disable matching resources with service appointments based on their territories. Deselecting Working Location Enable Primary on the Working Territories Work Rule would not affect Universal Containers' scheduling policy because it is already deselected by default. References:
https://help.salesforce.com/s/articleView?id=sf.fs_scheduling_policies_work_rules_working_territories.htm&typ
https://help.salesforce.com/s/articleView?id=sf.fs_scheduling_policies_work_rules_match_territory.htm&type=5