When I was younger someone said to me: the point of sport is for you to win. The point of a game is for everyone to win. Your a gamer". Maybe a little simplistic but it does have a point.
So here are some reasons I larp, and frankly, so should you:
It's hugely diverse: people who think there is only fantasy larp, you are wrong. In a single month I could play heroic larp combat, historical or realistic larp combat, no combat, modern day, Sci fi, historical, horror, small (10-20 people), huge 2k, indoor, weekends camping... etc etc. It's huge. There is something out there for you.
Perspective is everything: you can play, more or less, anyone in a larp. You get to try and consider stepping into other people's shoes safely. Thinking about why a character would do what they do. The thought processes that lead to that give you a strong skill set when dealing with other people.
Stage craft & confidence: you will learn to emote. To talk to people. To share stage space & grab the limelight. You will learn why it's fun to be a minion or a foible or the straight man.
Skills: you will pick up some weird & wonderful skills. Mainly costuming. Sewing. Cooking. Fire building. Wax sealing. Stripping a machine gun. Characters (and for camping events survival) demand learning all kinds of practical skills.
Learning: I have learned so much from larp. A truly amazing amount. I have learnt about history, politics, medieval wool trades... it's ridiculous.
Fitness & fight skills: from learning to shoot a variety of perioud firearms, sword fighting, bottling people. The noble art of running away...
You learn to keep your eyes open. To be aware of your surroundings. (Because running into tree stumps hurts).
Team work: either because your helping run the events or you need to work as a team to finish a plot, you learn to work together.
It's childish: no. That's a good thing. There is no lost art of play. Only a forgotten one.
I've been a victorian grave digger/night soil man fighting of zombies with a spade, I've worn a pot on my head as goblin militia, I've been the incredibly serious saxon noble accused of murder, I've been an oriental monk, a viking storyteller, an elderly priest who can't shut up, a misbegoten slave, a judicial knight etc etc.
So that's it. Find your local system.
And if your already larping: go find something new & stretch yourself!