It is preferable to extend the Salesforce B2B Commerce remote invocation object instead of using the standard Salesforce remote action invocation manager for two reasons:
The APEX method called by the remote action will be passed as a Salesforce B2B Commerce context object, which contains useful information such as the current user, cart, storefront, and configuration settings. This can simplify the development and testing of the remote action.
The Salesforce B2B Commerce logger can be utilized in the remote action, which allows logging messages and errors to the debug log or to a custom object. This can facilitate debugging and troubleshooting of the remote action.