head to head
Neither is meaningfully harder - they pose close to the same test. The widest gap is reads, and it is a single point.

Execution · Competitive PvP
Combo execution and endless mixup prediction against adapting human opponents.

Reads · Competitive PvP
A platform fighter where edgeguards turn on reading the opponent.
Persona 4 Arena leans Execution (Competitive PvP); Super Smash Bros. Ultimate leans Reads (Competitive PvP).
Same score on execution - which means the number cannot separate them. The difference is in what each one asks of you.
Persona 4 Arena
Combo execution and confirm timing gate competitive play
Super Smash Bros. Ultimate
Tech skill, edgeguards, and DI are mechanically heavy.
Super Smash Bros. Ultimate leans a little harder on reads, though the gap is small.
Persona 4 Arena
Mixups and throw-tech guessing against adapting humans never converge
Super Smash Bros. Ultimate
Adaptive opponents drive ledge and platform mind games.
Super Smash Bros. Ultimate leans a little harder on variance, though the gap is small.
Persona 4 Arena
Almost nothing random in a fighting match
Super Smash Bros. Ultimate
Stage hazards and items if enabled.
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
Persona 4 Arena
Frame data, matchup study and meter math reward homework
Super Smash Bros. Ultimate
Matchup knowledge and kill confirms are learnable.
A matching score does not mean a matching test. Two games can both sit at 10 on execution and demand completely different things of you - which is why the reasoning above matters more than the number beside it.