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.

Execution · Practiced Mastery
Precise shot aiming plus planning the run-out several balls ahead.

Execution · Practiced Mastery
Plannable stealth routing punctuated by precise ballistic marksmanship.
8 Ball Pool leans Execution (Practiced Mastery); Sniper Elite III leans Execution (Practiced Mastery).
8 Ball Pool leans a little harder on execution, though the gap is small.
8 Ball Pool
A perfect aim-line cheat wins nearly every rack outright
Sniper Elite III
Ballistic long shots demand steady, compensated aim
8 Ball Pool leans a little harder on reads, though the gap is small.
8 Ball Pool
Opponents alternate turns; little adaptive interaction to predict
Sniper Elite III
Enemy AI follows mappable alert and search routines
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
8 Ball Pool
Break spreads add some randomness to each rack
Sniper Elite III
Patrol details and wind vary slightly per attempt
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
8 Ball Pool
Position play and run-out planning separate good players
Sniper Elite III
Open maps reward planned routes, sound masking and relocation
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.