This doesn't even have to be a metaphor, there are literal cults based on literal aliens. Some of them are quite large and influential. The non-organised ones

This doesn't even have to be a metaphor, there are literal cults based on literal aliens. Some of them are quite large and influential. The non-organised ones though, I think make people feel good for themselves by either making them feel important(advanced civilisation came across the universe for me) or reassured (it's going to be alright, the universe works as expected - no funny business)