The cryptocurrency price shown on both sites are the average price from the exchanges they're getting their data on.
Lets put bitcoin as an example.
On worldcoinindex, they're only taking data from 18 exchanges. Whereas on coinmarketcap, alot more than that (400) since not only they're taking data from more exchanges, but also because coinmarketcap is also taking data from different pairs like BTC/JPY, BTC/SGD, etc.
So to answer your question: coinmarketcap is more accurate.
Very well said.This post is the answer regarding on their differences.
Coinmarket does update the prices immediately as compared to worldscoindex and if you see the websites, the prices are updated in real time unlike the other site. However, sometimes there isn't much trading volume on exchanges and hence the prices are shown after gaps of 3-4 hours.
This is what I like on coinmarketcap this is why I do always use it compared on worldscoindex.Updates is important to me because I'm an active trader and I would like to know informations or prices as fast as possible.