What is the purpose of CoinGecko?

Could you tell me, in brief, what is the fundamental objective behind CoinGecko? I've heard it's a popular platform in the cryptocurrency space, but I'm not entirely clear on its purpose. Is it a mere aggregator of market data, or does it offer more comprehensive insights and services to users? Also, how does it differ from other similar platforms in the market? I'm eager to learn more about its unique value proposition.