Not sure anything is enhancing. Approaches have… always been documented? What has greater range - VORs? I haven’t seen any. I think it’s reducing everything to MON that’s it.
See AIM 1-1-8. NAVAID Service Volumes https://www.faa.gov/air_traffic/publications/atpubs/aim_html...
"documented network of airports" is a poorly worded reference to MON airports as distinguished from MON navaids.