head to head
Neither is simply harder - they are hard in different places. Marvel Snap demands more variance; StarCraft demands more execution.

Reads · Grand Arena
A fast card game where the snap mechanic makes reads central.

Optimization · Grand Arena
A real-time strategy classic where perfected build orders and mechanical speed decide most matches.
Marvel Snap leans Reads (Grand Arena); StarCraft leans Optimization (Grand Arena).
StarCraft leans clearly harder on execution.
Marvel Snap
No execution component
StarCraft
APM and micro control ceiling is huge
Marvel Snap leans a little harder on reads, though the gap is small.
Marvel Snap
Snap/retreat decisions are pure opponent psychology
StarCraft
scouting and predicting human opponent builds
Marvel Snap leans clearly harder on variance.
Marvel Snap
Hidden locations and draws drive swings
StarCraft
minimal hidden info beyond fog of war
StarCraft leans clearly harder on optimization.
Marvel Snap
Deck construction and curve still matter
StarCraft
build orders and economy are near-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.