Now I have no real urge to do it over and over (though anyone who completes it has to get really good at it and it is fun - like an old school very hard platformer) but you can do this with MF gear on for lots of Trick or Treat bags after you loot the Mad King's Slippers the first time.
It's < 3 minutes a run (or you'll already have failed) so in that sense it's not bad farming. It's certainly novel.
A better alternative though is the dungeon. Get 4 like minded individuals and you can run this real fast with a chance at exotics in the chest at the end. It takes no more than 15 or 20 minutes once you get in the groove.
I hear rumour's that there's also a chance at really rare items - the Halloween items. So that's definitely worth doing if you've lots of time and have already made all the Halloween investments you care to.