According to the SAP Help Portal, you can use a custom end-user personalization configuration for various purposes, such as assigning it to an access request template, determining roles that can be assigned on a request, and determining fields shown in a workflow item. Assigning it to an access request template means that you can customize the user interface and functionality of a specific template. Determining roles that can be assigned on a request means that you can restrict or allow certain roles based on criteria such as role type, role level, or role owner. Determining fields shown in a workflow item means that you can hide or display certain fields in the access request form.