No, it's really not stupid at all. If he were our ace, then sending him to AAA just because he has options would be stupid. But we are currently looking at him to fill a #4 or 5 slot in our rotation, which Pomeranz or Wright (or Buchholz until he was traded) could have filled just as productively.
If you risk losing a player that might really help the team, then you send the guy with options down, at least for a while.
All that said, trading Buchholz alleviates some of the backlog of pitching roster spots, so there is less of a need to send ERod down.