And palantirs caused unhealthy obsession in people who touched them, just like the internet.

They were also essential to winning the war. Sauron got just as fucked over by it as the people he tricked with them. Basically it causes a Vulcan mind meld between any people using it and there used to be more and they were kinda like a bunch of pay phones on a party line. Sauron got Denethor to the point he was at by showing selective truths, Denethor had essentially the same Right as Aragon to use the palantir so they could both use it to their advantage which Denethor believed he was doing and gathering intel but he got shown how fucked he was and was having a bad time coping, sauron knew a hobbit had the ring and when pippin looked at the isengard palantir Sauron figured that pippin had the ring (there’s a whole lot at the end of fellowship and start of two towers that clarifies why sauron was so slow to get the news that saruman was both for sure trying to get the ring for himself and also had been defeated. A few days later Aragon rings him up on the palatir and shows off the sword that kicked his ass last time and says he’s coming to do it again. Sauron figures Aragon took the ring from pippin and its gonna be used in a war and goes full war mode and leaves mordor easier to get through. Plus they were made by Feanor who is like…the shadow the hedgehog of Tolkien