If BFG can be in the top 100 lists, they will attract more investor to invest in their project while they can also playing gambling in their site.
I guess their plan is not anywhere close to attracting more investors... they are a casino, and they want to attract more players, and they doing that by investing in different promotions and on-site perks. BFG is just one of the perks... by holding them (staking) on the site you get some coins, or you can stake them to get more BFG. You can also use it for gambling if you want to.
Maybe they will change the course one day, or maybe not... I guess we will see.