If it were actual (autonomous) robots, yes. The article is actually talking about ROVs (remote-operated vehicles). The city still needs to pay a human operator, who happens to be a moderate distance away.

It's arguably financially justified in the policing case because policing can be dangerous. Cleaning up [stuff] and sanitizing things isn't particularly dangerous, so you're basically just buying a robot to make your janitor less efficient.

In Singapore maybe .. this is America! If there's anything we're good at domestically, it's using lethal police force.

No it would be equally as helpful except that part will never get funding while drones that take the burden off of police will.