Their listing on coinmarketcap is not exhaustive. I prefer to use coingecko because they update more quickly and fully even the crypto scams and they offer brief explanations and advice on trading them.
I prefer to use Coinmarketcap because the site has everything I need and it will definitely be a lot more accurate than Coingecko. However, Coinkecko updates new coins very quickly, which attracts a lot of people to come. Of course, everyone will have different choices but I prefer the top Defi at CMC because it's transparent and really detailed.
Coinmarketcap recently had too many users and it could be overwhelming. Yesterday, I have been following and contrasting some cryptocurrencies I noticed that Coinmarketcap is updating its exchange rate more slowly than Coingecko. I think coingecko is better and easier to observe, convenient, complete, and faster to update. I am thinking of using coingecko for the long term for trading and keeping track of my favorite cryptocurrencies.