Off-beat means using the unstressed beats instead of the expected ones. That is demanding, because you must not lose sight of the basic pulse: dancing beside it without knowing where the beat is, is not off-beat but simply wrong.
The workshop practises exactly this double task — staying with the pulse inside while stepping beside it outside. Used well, it creates a tension the music audibly takes up.
What you take home
The confidence to dance against expectation on purpose — and to know when it suits the music.