Imagine if Bitcoin decided that its base unit will no longer be a Bitcoin, but a Satoshi (one 100 millionth of a Bitcoin). The more valuable Bitcoin becomes, the more likely that the Satoshi will be the measure people use for value. Just because one Satoshi is worth USD$0.00015 while GRC is worth USD$0.16 doesn't mean that compared to GRC, sats are practically worthless (you just have more of them, each worth less individually).

The market cap is the total value of a coin - if you could sell all coins at current market price. For GRC that is around USD$61 million, while for BTC it is USD$259 billion. BTC has the highest market cap of all coins.