Meh, what would be your great response to Tree + Water?
A human can only generate a small fraction of the combinations and would have a hard time coming up with most combinations which are already nonsensical.
What is your non-disappointing idea for, idk, Tears + Pottery (AI: Bowl) or Money + Salt Lick (AI: Cow) or Skull + Lake (AI: Loch Ness) or Dracula + Pirate (AI: Vampirate) or Curse + Money (AI: Debt)? Now do that thousands of more times.
The infinite aspect is the thing that keeps it interesting, I think. The fun is getting a new, weird result like "Dracula" and "Pot of Gold" and seeing if you can generate new weird results from the existing set.