Iterating button colors gets you 0.x% wins while the real 15% sits in a structural change you never test.

Iterating button colors gets you 0.x% wins while the real 15% sits in a structural change you never test.
The mistake: optimizing toward a local maximum — endless micro-tweaks on a checkout that should be re-architected (guest checkout, fewer steps).
— Small safe tests crowd out the big risky one.
— Fix: budget ~20% of test slots for bold structural variants. Measure the ceiling (best-case flow) so you know the gap you're leaving.
Read the number, not the story. [micro 0.x% vs structural ~15%]