Hello,
Because the unique mining algorithms:
1) Lowest mining difficulty, then we did not need long time to find block.
2) Your wallet need receive coin (per 4321 blocks), then can mining.
3) Queuing mining, when you find one block, you need wait 60 blocks, other did not find block's miner can continue mining.
Resistance ASIC and botnet,
4) As this mining rules, gpu no advantage, most pepole will use cpu to mining.