Four people in my life have made this choice. Two chose the girl, two chose the job. Of the two that chose to stay both got divorced, one killed himself. N=2 is not a good sample size so take that for what you will. The two that chose the job are both doing OK; the introvert is having a bit of a trouble making a new social network, but the internet lets him stay in contact with the old network. Both of the men that chose to leave left a relationship for a job that made more than twice the median, both men left to pursue "dream" jobs that only come around once or twice a lifetime if you are lucky. N=2 is not a good sample size so take that for what you will.
We're both young, untethered by relationships, and with skillsets that aren't geographically limiting.
You will only be young and untethered once in your life. If given the chance to move and get to experience a new part of the world, and not have to live like a hobo, why not? I went and worked my ass of in Alaska. Another person in my life moved all the way across the country to go to a community college to get the hell away from a toxic family; once the mental energy of that nonsense was off his shoulders he flourished. You also have the bonus of taking a friend with you. Going out and doing stuff is a lot easier with someone at your side, right?
It almost feels like change for the sake of change but I think there's more to it than that.
Where I am now gets a lot of 'boomerangs' for lack of a better word for it. These are people who said "this place sucks" went out and worked or went to school elsewhere then discovered that the Ohio Valley is not really all that bad and came back with some life experiences, fun stories, skills, a different outlook on work and family and seemed at least to me to come back a better person. Travel opens the mind, and if nothing else working in a different state or country for a few years will give you some good stories to open with at gatherings. I'm still introduced as "the insane guy who worked on a boat in Alaska" to new people in the friend group.