Yeah, the bots aren't all that smart. I had a bot once trash his deck down to Alchemist, Potion, Chapel, and Silver. There's wasn't anything worth 2 coins other than Chapel, so he didn't buy anything for the rest of the game.
And if you want a REALLY easy game, just spam Torturer. They always
discard, even if they have moat/watchtower/chapel/etc., and even if the curses are gone.
By far, the funniest thing I've seen is a bot playing Ambassador and returning 2 Provinces to the supply!
The developers know about the bad bots. Hopefully they fix them soon...