I grew up in an entire family who had fallen down this slippery pipeline of magical thinking. For some of them, it cost them everything.
It's almost entirely bullshit designed to prey on people who are desperate for something better in their lives, desperate to feel less alone, desperate to feel hope that the universe is bigger than it seems and that they won't die or have to say goodbye to everyone someday.
That's where it does the most harm, along with religious beliefs like the rapture or Armageddon fantasies, it's just magical thinking that makes you feel like nothing on Earth here and now matters. No need to worry about the climate, Jesus/Aliens are coming. No need to get educated and invest in your future, Jesus/Aliens are coming. No need to value your every moment like it may be your last, because Jesus/Aliens are coming, you have all the time in the world to ignore the people and precious memories around you.
The most fucked-up part of it all is I think there may be something weird going on, but it's not aliens or jesus, it's not an escape, it may not even be an "objective" thing, but maybe some natural phenomenon that our brains are recontextualizing. But this kind of "maybe there's something real" event seems to be exceedingly rare and without a way to study or replicate it, without valid, unambiguous evidence, it's like any of our own subjective experiences, it takes place inside you and can't impact the world around you. If you think it will, you will end up alone and disappointed.