The Champion Badge is awarded to players that have defeated the Elite Four and more importantly, the Champion.
Once you have the badge, and you own the "x2 pokedollars" game pass, your bonus will increase to "x3" when obtained.
The Champion Badge allows players to catch new Pokémon. These Pokémon being:
For ownership of the Champion Badge, Members of the Project Pokemon Community group will be awarded the Champion Rank which gives them a Light Blue name in the game Leaderboard, as well as the rank below their name on their trainer card.