You get it in cash if you join the bank, at which point said cash will be paid into vitality savings.I do. Gym booster used to be more straightforward. Vitality gave you 75% discount and you could get the remaining 25% back by achieving your active rewards goal every week. That’s no longer the case with bank... Much more complicated for new members. Members on the legacy gym booster benefit still get the 25% back (your friend being one of them). But from 2020 the 25% back will be paid as miles instead of cash for them.
Vitality members who joined VA before 2010 get 100% by default without gym booster.