"Steven P. McNicoll" wrote:

"Daniel Roesen" wrote in message
...

Hm, for what reason? Cheaper for your specific route(s) to that
destination than the published approaches?


Because there are no published approaches.

Special instrument approach procedures may be for a location that
doesn't have a public IAP or it may be at a location that does have a
public IAP. An example is KRNO where the special ILS lowers the
minimums by several hundred feet.