head to head
Neither is simply harder - they are hard in different places. Marvel vs. Capcom: Infinite demands more reads; StarCraft demands more optimization.

Execution · Grand Arena
A Stone-powered tag fighter where Infinity Stone selection and team synergy drive the competitive meta.

Optimization · Grand Arena
A real-time strategy classic where perfected build orders and mechanical speed decide most matches.
Marvel vs. Capcom: Infinite leans Execution (Grand Arena); StarCraft leans Optimization (Grand Arena).
Marvel vs. Capcom: Infinite leans a little harder on execution, though the gap is small.
Marvel vs. Capcom: Infinite
Infinity Stone tag combos require practiced execution
StarCraft
APM and micro control ceiling is huge
Marvel vs. Capcom: Infinite leans clearly harder on reads.
Marvel vs. Capcom: Infinite
Stone selection counter-picks and team tendency reads against humans
StarCraft
scouting and predicting human opponent builds
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
Marvel vs. Capcom: Infinite
No RNG; all information is visible
StarCraft
minimal hidden info beyond fog of war
StarCraft leans clearly harder on optimization.
Marvel vs. Capcom: Infinite
Stone pairing meta and team routing reward structured study
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.