You can hold your Litecoin in coinbase because Coinbase safe & very esay Wallet.Mobile app & Web wallet both supported.
not to mention a web wallet or a third party which means if you store your litecoins there it will be in their 100% control and you won't even have access to your private keys. coinbase can go under or run away or block your account or you may even get hacked and lose all your LTC.
i'd say as long as there are better options such as light wallets (Electrum) and paper wallets (liteaddress.org) there is no point in using a web wallet.