Hardware wallets are not cold storage, though my take is that they provide roughly the same level of security and I would recommend hardware wallets over cold storage for newbies.

I think the important distinction is that suppose any thing were to happen with your CoinBase account, for example malware attacks on your part and the coins got out of the account, they're not liable for the losses because the negligence is on you. It will not insure you for most attacks but rather, it'll insure you if THEY lose the funds. That makes it nowhere as beneficial a HW wallet/cold storage.