wow,when we sell ?

Never ... we let the value grow and we slowly get merchants on board... then we use our coins as currency. No selling out to fiat or BTC.
100x this. Originally I was into this to increase my BTC but now I realized that PoS is a better system. Requires less energy, has faster confirmations. It is imply the next step in cryptocurrency. Bitcoin popularised cryptocurrency like Naspter popularized p2p networks, but there are technological advancements that need to be made. Blackcoin will not be the last step, but it is the next step.