Bounty Chocolate

Basically, why is a premium chocolate bar called premium?

"Bounty" means treasure, reward.

Thus, the Bounty bar is your reward .........

Nice, simple name. Easy to say, easy to remember. Good product identification (reward = good thing).

and there are lots of reasons,
one is that the person on top said and what I think is that he has a picture of a beach / island and the treasures of history and hunting, pirates, etc.
a premium and could suggest a treasure or reward as the guy on top said.