Only online. Since even a smidge of uneven lag/delay on the non-Falcon's side just sets them up to be "bodied" or something. Especially if using average speed characters.
To be fair, in a game where most KB angles are upwards or diagonal, most bad recoveries aren't as risky to have. Being fast overall allows him to get the hell outta dodge, allowing him to take away some of the opponent's momentum without actually even attacking. And ofc being fast makes his Dash Attack/Grab pretty powerful vs a nice chunk of the roster - bcuz - oops slow gorls/bois.
He is still a strong/not low-tier character and he's fast with nice sized hitboxes for a character who just uses his body
(rip WFT). But he's not as easy to harass with as he was in Sm4sh. Because, like, he's kinda balanced and stuff now. His Side-B could be a bit stronger though imo. And in a game where some characters are extremely/good or safe to play, using him just doesn't make sense if he was used more for tier-reasons and not for-fun-reasons.
I suppose it's because using a character with a weighty enough weakness is a scary thought to some.