One potential reason I can think of (and note that there could be other reasons) is that SailPoint allows for requesting access from multiple sources: It could be a catalog integration like ServiceNow Catalog, it could also be an integration with tools like MS Teams or Slack, or just the good old request center.
In cases where a client/customer does not want to use the OOTB request center, but leverage one of the other two options, you can have your accesses still be requestable, but toggle the viewing/requesting of that access from the Request Center off. I’ll let the experts provide more info if needed.