Some might ask: Why did the Riddler have to paint them out? Couldn't he have notified Superman some other way that didn't ruin the city's appearance? Like sending a letter?
In the original comics, the Riddler had all sorts of ways to deliver riddles to Batman, but that was Batman.
For one thing, Batman had a fixed address, or at least a regular patrol route, and legitimate means of contact. Whether the Riddler sent a letter, an email, or launched fireworks, he could at least find a fixed destination.
But Superman, weakened by his body and unable to find a proper job, had been wandering the dream world the entire time. At first, he could still stay at shelters, but later, people at the shelters kept harassing him over his appearance, so he stopped going there altogether.
The Riddler had no way to send a letter to a homeless man through normal channels. He could only hire someone to deliver it, which was far too troublesome. The courier might arrive only to find that Superman had gone somewhere else, or Superman might be there while the courier took the money and did nothing.
And speaking of money, the Riddler wanted to cry even more. He was neither a lawyer with an illustrious professional record like Harvey nor a successful businessman like Penguin, who could make a living anywhere. He was not even as quick-witted as Harley Quinn. Yet they all still had to eat in the dream world.
The Riddler's sources of income in the real world were rather mysterious. The comics rarely developed his professional background, at most mentioning that he had worked as a deliveryman and a consultant. In the television series, he had a stable job at the Gotham Police Department, but it did not look like