SID vs ODP
 

We all know that Standard Instrument Departures are there basicly to make it easier on the controller, and Opstacale Departure Procedures are there for opstacle clearance. Alright, then why does a very low traffic place like FMN have SIDs? (why don't they just call them graphical ODPs!) Also, BZN has a graphical ODP and SIDs but they look pretty much the same. And lastly, why are airlines filing this graphical ODP in their flight plan at BZN? I thought ATC didnt have to know about ODPs?

No idea where this place is... but guessing, noise apatement?

Or could it be that this place is in the vicinity of another, bigger, airport which is the primary reason they produced a SID for the area in the first place?

Edit: I see now FMN is in the US and they are easily "browsable" with Airnav: AirNav: KFMN - Four Corners Regional Airport

Seems like the only airport serviced by the 2 SIDs there. Probably the only airport in the vicinity operated by airlines of some kind and SIDs are programmable in FMC ;)