head to head
Cossacks 3 asks more than Fallout: New Vegas, and the gap is reads.

Optimization · Pure Optimization
A large-scale real-time strategy game about massive army economies in the 17th century.

Optimization · Pure Optimization
A faction-driven RPG-shooter where build and route planning shape every ending.
Cossacks 3 leans Optimization (Pure Optimization); Fallout: New Vegas leans Optimization (Pure Optimization).
Fallout: New Vegas leans a little harder on execution, though the gap is small.
Cossacks 3
unit micromanagement under real-time pressure
Fallout: New Vegas
Shooter inputs with VATS assist
Cossacks 3 leans clearly harder on reads.
Cossacks 3
human opponents bluff builds and attacks
Fallout: New Vegas
Scripted factions and enemies
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
Cossacks 3
minor combat outcome randomness
Fallout: New Vegas
Some loot and crit RNG
Cossacks 3 leans a little harder on optimization, though the gap is small.
Cossacks 3
massive army economy and tech optimization
Fallout: New Vegas
Faction routing, perks, builds heavily 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.