I was confused about this myself until I came across a good explanation. In short, sweeps coins are a virtual currency used in sweepstakes casinos. They differ from regular gold coins in that SC allow you to claim rewards, rather than just playing for fun. I read a article on Sportzino about
what are Sweeps Coins, and it explains that SC can be obtained for free: through daily bonuses, promotions, referrals, or even mail requests. In general, this is the key difference from traditional online casinos. I think that's why they've become so popular. Have you registered yet? If not, I can help you with that.