How does one benefit from playing in OTB tournaments?

I've heard many chess players say that playing in OTB tournaments is indispensable for improving one's chess. Why is that the case? I'm no stranger to playing in OTB tournaments, and I've never felt that I've gained anything from taking part in them, or at least not more than from playing online. As a chess player I have improved by studying openings, solving puzzles, watching broadcasts with commentary by GMs and IMs (as well as chess videos on YouTube), reviewing my games with engine help, but not by playing in tournaments.

Could someone please explain the benefits of playing in a real-life tournament to me?

      Its called LIFE; to enjoy it, you have to show up. You can't hide behind a computer screen forever.

Besides the obvious advantage of playing face to face, one big advantage is the opportunity of asking your opponent for a post-mortem analysis of the game you've just played. Sort of a free lesson if your opponent is stronger than you.

there are certain elements in otb chess that u dont get online, like once i was watching a tournament, the guy was staring the other guy very rudely 100% of the time, not a tal-like stare, but the kind of stare that says "ur despicable, look at me, dont look at the board, i dont respect u at all."

 If its ur first time otb tournament game, that can affect ur performance of the game.

OTB chess tourney is real chess competition. Online chess and playing against programs are just sparring sessions. If you want to know if you're good at chess, try OTB chess tourney. 

I'll play my first OTB tournament next month, IF I can secure that required FIDE number. Expect to lose every game, same as here - tumbling towards a 0 rating 

The benefit is you're competing in a venue where everything counts.  All those chessbooks, all those practice games, all that coaching is for those moments.  There's also a uniform time and color ratio is even usually so you get even experience with white or black (though one time I had white three times so I played 1.a3 hoping to enter a reversed Leningrad Dutch with

But they played 1...e5 so I simply entered a Paulsen Hedgehog with 2.c4 a tempo up. 

Playing the computer, all you do is move your mouse around a little bit and click with your index finger. It's very sedentary.

However, in an OTB tournament, you stand up and walk to the next table, work out your arms and shoulders by dumping the pieces out and setting them up, practice your penmanship by writing down the score, and get to touch actual pieces and punch an actual clock. Obviously, the exercise benefits alone are worth the entry fee.

Plus, you get the self-esteem boost of walking around looking at all the geeky guys who showed up on this beautiful sunny Saturday to play chess, saying to yourself, "Oh, yeah, I'm at least cooler than HE is."