head to head
Path of Exile asks more than XCOM: Enemy Unknown, and the gap is optimization.

Optimization · Pure Optimization
A theorycraft-dense ARPG about engineering builds through randomised loot and crafting.

Optimization · Systems & Chaos
Managing RNG-driven combat while solving the underlying base economy and research tree.
Path of Exile leans Optimization (Pure Optimization); XCOM: Enemy Unknown leans Optimization (Systems & Chaos).
Same score on execution - which means the number cannot separate them. The difference is in what each one asks of you.
Path of Exile
Some dodge and reflex play, but build carries fights.
XCOM: Enemy Unknown
Turn-based; no twitch inputs; cover placement has mild precision
XCOM: Enemy Unknown leans a little harder on reads, though the gap is small.
Path of Exile
Mobs and bosses are scripted; no adaptation.
XCOM: Enemy Unknown
Aliens follow scripted AI, never model your specific habits
XCOM: Enemy Unknown leans a little harder on variance, though the gap is small.
Path of Exile
Loot, map mods, and crafting outcomes are heavily random.
XCOM: Enemy Unknown
Hit chances, crit rolls, and mission spawns create constant RNG swings
Path of Exile leans clearly harder on optimization.
Path of Exile
Passive tree, crafting, and economy form near-infinite theorycraft.
XCOM: Enemy Unknown
Squad composition, research order, and base economy are solvable
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.