Without wading into the tangential discussion, here is the answer to the specific question asked:
The menu option you are seeing is confusing, because it is also used for OBi 202 configuration. 202's have two physical phone line jacks, and, if you had a 202, it would display check-mark boxes for both of those phone lines. In that scenario, you'd decide and select which of the two physical telephone lines to ring on inbound calls -- Phone 1 or Phone 2, both, or neither; your choice. For example, you may have a SP that you only use for outbound calling, and you don't want to be bothered if it gets an inbound call. Since the 200 only has one phone line jack, it is only showing Phone 1. Checking the box (by default) will ring the attached phone. Not checking the box will...you guessed it, disable ringing the attached phone. That's all there is to it.
See the attached screenshots.