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

Optimization · Pure Optimization
God game about winning worshippers through miracles and training a giant pet creature.

Optimization · Pure Optimization
Mobile production-chain and layout optimisation paced by timers.
Black & White leans Optimization (Pure Optimization); SimCity BuildIt leans Optimization (Pure Optimization).
Black & White leans a little harder on execution, though the gap is small.
Black & White
Gesture-cast miracles; minimal dexterity stakes
SimCity BuildIt
Tapping menus has no skill floor
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Black & White
Rival gods follow scripted strategies
SimCity BuildIt
No adversary; trade is asynchronous
Black & White leans a little harder on variance, though the gap is small.
Black & White
Creature learning quirks surprise first plays
SimCity BuildIt
Market prices and material drops add mild randomness
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
Black & White
Village economy, belief spread, and creature training
SimCity BuildIt
Production chains, layout and currency timing are the whole game
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.