Each Robin has proven themselves to be worthy of being Batman's sidekick, but Damian was once the most powerful Robin ever when he acquired actual superpowers. Even before becoming a fully-fledged (albeit temporary) superhero, the son of Batman was already a force to be reckoned with.
Having been trained by the League of Assassins since birth, he believed his skills were already beyond those of his father, let alone the other Robins, and he often goes out of his way to prove his superiority.
Before even taking on the mantle, he confronts Tim Drake, who was Robin at the time and sent him flying across the Batcave with a single punch. Once he officially becomes the Dark Knight's sidekick, he attempted to prove himself by defeating all the previous Robins in combat, and even though he was successful, he didn't exactly fight fair. His true danger, however, comes from his more lethal tendencies. Before becoming Robin, he beheaded a crime boss named Spook, and he once defended Batman's identity by killing a former acquaintance of Bruce's named Nobody. While he mostly restrains himself from murder these days, he is still no less dangerous, doling out justice in a most brutal fashion. So how did this ex-assassin gain Superman-level abilities, and what did he do with them?
Firstly, he died in Batman Inc. #8 by Grant Morrison, Chris Burnham, and Jason Masters. He is killed by The Heretic, an advanced clone of Damian himself created by his mother, Talia al Ghul. Batman refused to accept this and sought to find a way to bring his son back to life. Ra's Al Ghul stole Damian's body and put it in a sarcophagus that contains a Chaos Shard, a powerful crystal that belonged to the New God Darkseid. The coffin was then taken away to Darkseid's planet of Apokalips, who planned to harness the power of the crystal, and Batman formed a plan to bring his son back. In Batman and Robin #38 by Peter J. Tomasi, Patrick Gleason, and Mick Grey, they teleport to his planet and he tricked Darkseid into charging the Chaos Shard using energy called the Omega Sanction and used the power to resurrect his son.
In Robin Rises: Alpha by Peter J. Tomasi, Andy Kubert, and Johnathan Glapion, it was soon discovered that Damian is not only alive but super-powered. Darkseid's son Kalibak invaded the Batcave to kill them all, and Damian fought him off almost single-handedly. He could fly, was super-strong and super-fast, was insanely durable, and even had laser vision.
A Batman with superpowers would be worrying enough, but an occasionally homicidal mini-assassin trained by Batman is a little more concerning. Luckily, he used it for little more than showboating. He allowed criminals to shoot at his bulletproof body, he ripped apart a tank with his bare hands, and even terrified a group of criminals by threatening to crush them with the Bat-signal. Even poor Alfred suffered at his hands, with Damian accidentally crashing through his floor after a nightmare, and occasionally using the butler to juggle with. That being said, he does use his abilities more compassionately at one point, going to Atlantis by swimming two and a half miles underwater to release the failed and deformed clones of himself that his mother had tried to hide from him. He also comes into his own when he joins the Justice League on a mission to take out a giant robot, although it turns out to be a ploy by Batman to drain Damian of his powers.
And drain him it does. By the end of Batman and Robin #40, again by Peter J. Tomasi, Patrick Gleason, and Mick Grey, Damian Wayne is back to being the regular Boy Wonder, much to his despair. Bruce, on the other hand, is glad to see the powers gone, knowing how tempting and dangerous having those kinds of abilities can be.
Although Damian Wayne's super-powered exploits were short-lived, aside from a few moral bumps in the road, he managed to use his abilities for the betterment of people around him, even if it was in his own unique way. He may no longer be more powerful than a locomotive, but that doesn't make him any less a hero, or any less dangerous.