Coinbase is one of the biggest crypto trading platforms in the world. Main reason for there succes is the easy way to buy and sell crypto's. This ease of use comes at a price though, because the fees are very high.
If you are looking for easy access to buy crypto's and aren't trading a lot, then this can be the right platform for you. If you want immediate access to your funds you can use iDeal to transfer fiat to your account.
If you invest for the long term, it is always best to not keep your cryptocurrencies on the exchange. We recommend you transfer your money to a hardware wallet like a Ledger Nano