WARNING: The following contains spoilers for Superman: Man of Tomorrow #5 by Robert Venditti, Paul Pelletier, Drew Hennessy, and Adriano Lucas, on sale now
Lex Luthor and his inventions tend to be deadly and destructive, especially when they're geared towards showcasing his skills and powers. His newest inventions are deceptively simple security cameras around Metropolis. However, these cameras have a lethal secret that could make them very useful for any schemes that Luthor has going forward.
In Superman: Man of Tomorrow #5, Lex Luthor's cameras turn the very streets of Metropolis into a weapon, and that gives this continuity's Luthor more power over the city than he's ever had before.
During a battle between Superman and the giant ape Titano, it's revealed that Lex Luthor has set up security systems all across Metropolis. This allows him to observe Superman's battles and actions, letting him chronicle all of the hero's previous acts. While watching, Luthor waits for Titano to knock Superman out, which happens after the monster gets in a lucky shot. In that moment, Luthor's cameras reveals their true potential by transforming into laser guns, and taking multiple blasts at Titano. These blasts quickly manage to bring down the giant ape, before announcing how "Lexcorp is happy to secure the city of Metropolis." Luthor quickly uses this technology to keep attacking criminals across Metropolis, grabbing headlines for his acts and becoming seen as a genuine protector of the city.
Luthor quickly forces most of the supervillains out of the city, with some even trying to make names for themselves in other locations, like Central City. Clark Kent and Lois Lane initially believe there must be a secondary reason for his actions, but there doesn't seem to be any: Luthor is just weaponizing the streets of Metropolis and using them to save the day. Luthor is able to give Metropolis 11 days free of any supervillain events, which implies that Lex is seemingly on the up-and-up about trying to do good by Metropolis. However, the tech proves unflinching in its "security," even preparing to kill a man for walking out on a check at a restaurant. Even Clark Kent standing in front of the man to shield him is considered a crime, which gets Kent blasted with the laser instead.
Lex Luthor has always wanted to be the most respected and beloved figure in Metropolis. The fact that Superman has always outshined Luthor has always driven him to dangerous and maniacal actions. One of his most consistent forms of trying to mess with Superman and steal his thunder is by posing as the true protector that Metropolis and the world needs. This has led to him creating his own heroes -- many of whom eventually turn on Luthor -- painting himself as an altruist to the world and even briefly becoming the President of the United States.
Usurping the guardian role that Superman provides for Metropolis would be a huge win for the supervillain, especially if it also gives him unfiltered access and footage from around the city. He could potentially use this access to force anyone in the city to follow his orders. Even the slightest breach of contract with Luthor and his laws could result in death by laser. By becoming a good hero for the city of Metropolis, Luthor may have just been handed all the power he needs to fully take over the city and defeat Superman once and for all.