Good to see other people pointing this out. The other thing people need to remember is that "gaining" or "losing" market cap in crypto has no relationship to how much money actually "came into" or "left" the market.

Another easy way to think of market cap is that it's the amount it would take to buy out the market if the entire supply was available at the current price. Of course, as soon as anybody starts to buy or sell, the price adjusts and so does the market cap -- and the entire supply is pretty much never available.

It's an interesting metric, but I think CoinGecko's ability to easily rank by other metrics is helpful. And it's also important to remember that crypto market cap rankings are getting increasingly crowded with Ethereum ICOs, which are basically crypto-kickstarters and arguably shouldn't be listed alongside actual coins. It would be like listing stocks, commodities, and real currencies together -- the major indexes I can think of all list and trade them separately for a reason.