Your Facebook or King profile will store and synchronize your progress along with any Gold Bars you have in the game, so your Gold Bars are always kept up-to-date and you won’t have to play any level twice.
Whenever you receive lives from your friends or win and buy boosters in any King games, these are delivered directly into the memory of the device you're playing on, and aren't synchronized by your player profile.
This is because your level progression and Gold Bars need to be constantly updated and synchronized as you play, so they require a stable internet connection. However, having your boosters stored in your device means that you can play while offline.
This means if you win a booster it'll be delivered only once, to the device you're playing on at the time, and it won't be visible across multiple devices linked to the same player profile. It also means you have the benefit of being able to collect separate quantities of boosters if you use more than one device to play.