In Webex Calling, locations group users or devices by geographical site and are used to manage PSTN access, whether on-premises or cloud connected PSTN. This allows calls to be routed appropriately based on the user's location and the associated PSTN trunk or gateway.
Locations enable linking to a specific PSTN provider or trunk (such as a Local Gateway or Cloud Connected PSTN), so calls from users in that location can be routed through the correct PSTN connection for local calling.
Locations also support inter-site dialing by using location codes and routing prefixes, helping maintain consistent dialing habits and call routing across sites.
While bandwidth management and data center selection are important, these are not the primary purposes of configuring locations in the dial plan for Webex Calling.
Therefore, configuring locations primarily facilitates local PSTN call routing by associating users with the correct PSTN provider or trunk based on their site.

Explanation:
Domain Routing: Required for routing SIP URI / domain patterns.
Unchecked (IPv4Pattern): This is an FQDN, not an IPv4 address pattern.
PT_INTERNAL: Makes the route pattern reachable by callers whose CSS includes PT_INTERNAL (CSS_INTERNAL).
SIP_CISCO_TRK: Sends the call to the specified SIP trunk.
ccnp.cisco.com: The destination domain to be matched; in this matching set it is placed in the remaining field (Block Pattern) due to the "use each item once" constraint in the question UI.