Coinbase wallet is a product of coinbase consumer exchange, the wallet was launched in 2018, it has support for some major coins like bitcoin, ethereum also you can store erc20 wallet in it, as well as erc721 collectible. You can also store some fiat currencies like USD, GBP, AUD, EUR in it.
Though most users of coinbase wallet also have account with coinbase exchange it must be understand however that they are 2 different things, while your wallet key for your account with coinbase consumer exchange is stored on coinbase server the key for coinbase wallet is store on the user's device.
They do charge fees for using the wallet, and the fees are not higher than what is obtainable in the crypto market, instead it is lower.
Coinbase wallet was backed by a renowned exchange and gives one access to varieties of financial instruments. Through the wallet users can interact with ethereum based Dapps with its integrated dapp browser.
It is not an HD wallet and the recovery phrase follow the BIP 39 standard. The wallet is secured and can be use with certain degree of assurance. The wallet is simple to use especially for the new comers into the crypto world.