Well, I'm a bit late coming to this party, but just noticed that HHonors points are no longer available as a MyPoints reward. I had accumulated enough for the Hilton reward but couldn't find it there, so came here to see what was up. Very disappointing - I agree as well that it is likely due to the new HHonors Shopping Mall (which I haven't checked out yet). I wonder about the explanation regarding delays in rewarding of points by Hilton - in my experiences, this has always been timely.
I fly UAL also so think that I will redeem for UAL miles. I will probably close my MyPoints account then to avoid getting the 10 or so emails every day. I still am a member of the eRewards program and AFAIK they still reward HHonors points, but I don't get many offers from them at all, maybe 4 or 5 per week.