It is bizarre. I recently booked a Milesaaver first/business award from IAD to SJD. I thought myself very lucky to find a departure and return about a week apart within a given month, departing and arriving from the same DC area airport, with a single non-overnight connection. Most options involved different departure and arrival airports, overnight layovers or triple connections in random nonhub cities. If you aren’t super flexible it’s useless.