Coinbase and other online cryptocurrency marketplaces give you a wallet with your account but there are other kinds of wallets besides that. There are online wallets which aren’t tied to marketplaces, there are software wallets tied to your local machine. There are so called hardware, which I think are usually or always USB. Finally there are paper ones.
Oddly enough, paper ones are considered most secure. Hardware ones are next, then local software ones, then online ones. The least secure are wallets tied to crypto marketplaces like Coinbase.
The reason online marketplace wallets are considered insecure are that periodically they are hacked and all their wallets drained. This used to be a problem in the early days of Bitcoin. I haven’t heard of it happening recently.
One of the biggest advantages of Coinbase is or used to be (when wallet transfer fees were high) that 2 Coinbase user could transfer crypto between themselves just using their account Email addresse).