Well, i won a national tournament using Falcon so i can talk.
When you play falcon in a tournament level you have to play him like a speedrun TAS game, you have to watch everything your oponent does and make the perfect response everytime, obv nobody is perfect and you can get rekt if you fail a punish, you can end fast an average player but you have to play very def an patient against top oponents because they will no miss any chance to hit you.
You have to master every move you have, up b for example can be used to gimp sometime, matering teching is important too, you have to learn a lot of match ups because there are a lot of characters that can punish Falcon easy.
Sometimes i find Falcon very stressful because you cant never play "safe" if you want to win you have to risk a little to hit your oponents, you can suffer against some characters because this, for example, Ganondorf can punish you SO hard if you do a little mistake when engaging.
BTW i think Falcon is right one of the best characters in the game.