head to head
Neither is simply harder - they are hard in different places. StarCraft demands more optimization; Street Fighter 6 demands more reads.

Optimization · Grand Arena
A real-time strategy classic where perfected build orders and mechanical speed decide most matches.

Execution · Grand Arena
A 2D fighting game where execution meets relentless yomi at neutral.
StarCraft leans Optimization (Grand Arena); Street Fighter 6 leans Execution (Grand Arena).
Street Fighter 6 leans clearly harder on execution.
StarCraft
APM and micro control ceiling is huge
Street Fighter 6
Frame-perfect inputs and combos are mandatory.
Street Fighter 6 leans clearly harder on reads.
StarCraft
scouting and predicting human opponent builds
Street Fighter 6
Adaptive opponent baits Drive Impacts and throws.
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
StarCraft
minimal hidden info beyond fog of war
Street Fighter 6
Essentially no randomness in match outcomes.
StarCraft leans clearly harder on optimization.
StarCraft
build orders and economy are near-solvable
Street Fighter 6
Matchup charts, frame data, and combo routes.
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.