Multi-armed bandit vs classic 50/50 split

Multi-armed bandit vs classic 50/50 split
Flash sale, 6 days, testing 3 banner variants. A classic A/B/C split wastes traffic on losers the whole time.
Multi-armed bandit: the algorithm shifts traffic toward the winning variant AS it learns. More conversions DURING the test. Perfect for short, high-stakes windows.
But here's where I got burned: I used a bandit for a long-term landing page test and it adapted so fast it never gave me a clean, reportable lift number. Bandits optimize earnings, not learning.
My rule:
— Short campaign, want max conversions now → bandit.
— You need a defensible 'B beat A by X%' for the team/roadmap → classic 50/50 split.
Don't reach for the fancy bandit by default. Pick by your goal: earn or learn. Report back.