They're there to waste your tickets so you'll buy more with diamonds, why else would they be there? I really hate landing on one of those spaces, though when a wheel comes up like that, I avoid spinning it until the junk gets cleared out or someone refreshes it. At least an avatar removes a space from the wheel permanently.
My main goal for the event was to earn a Champion's Retreat. I got that about 2 weeks ago, and picked up the Elephant Fountain and two matching pieces along the way, so I decided to go for the rest of the set. I finished it off a couple of days ago, and had picked up the Bandar Playground, so I then made an attempt for the Pond to complete the palace. Just got that earlier. So I go a decent return on the event.
I had some good spins the other day, most of the crap was cleaned off, leaving 2 Watchfires, two spaces with a free ticket and double tickets, an avatar, and a normal supply building. I cleaned off all the ticket spots, picking up another Watchfire and the avatar along the way, breaking even in the end.