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.

Optimization · Pure Optimization
A base-layout and attack-planning puzzle against static player defenses.

Optimization · Pure Optimization
A calendar-driven JRPG carried by persona fusion and social-link planning.
Boom Beach leans Optimization (Pure Optimization); Persona 4 Golden leans Optimization (Pure Optimization).
Same score on execution - which means the number cannot separate them. The difference is in what each one asks of you.
Boom Beach
Tapping troop deployments takes no dexterity
Persona 4 Golden
Turn-based, no input demand
Boom Beach leans a little harder on reads, though the gap is small.
Boom Beach
Attacks hit static bases - defenders aren't present to adapt
Persona 4 Golden
Scripted enemies
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
Boom Beach
Scouting reveals most info; matchmaking adds some spread
Persona 4 Golden
Weakness and crit rolls
Persona 4 Golden leans a little harder on optimization, though the gap is small.
Boom Beach
Base layouts, troop compositions and timing are the solvable core
Persona 4 Golden
Persona fusion and calendar routing rewarded
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.