It's a disciplined approach to explore vs exploit.
Just like the Kelley criterion tells you how to turn predictions into bets, the multi-armed bandit tells you how to keep a user engaged in the short term by showing them things you know they'll like but also keep them engaged in the long term by showing them things they might like occasionally which, if they pass the test, will expand the range of things that you know they like.
Just like the Kelley criterion tells you how to turn predictions into bets, the multi-armed bandit tells you how to keep a user engaged in the short term by showing them things you know they'll like but also keep them engaged in the long term by showing them things they might like occasionally which, if they pass the test, will expand the range of things that you know they like.