Coinbase carries only crime insurance. If they experience data breaches or attack and you lose money because of that, they'll give you a refund but Coinbase doesn't claim how much money they'll refund.
They also don't say how much money they have insured, so, if you lose $1000 because of their mistake, you might receive $1000 or $200 or nothing, no one knows exactly because even if they partner with other insurance companies and are insured, there aren't guarantees that insurance company will cover the losses. There have been many cases when insurance company turned into a scam in the end.
Okay but... what good is that?

They are saying they will "partially" make you whole, but they don't say what "partially" means? So somewhere between 99% and 0.01%? That is the same as no promise at all.
Exactly! They say that they'll give you some money back but do not state how much it will be. Even if they were about to state, you should never build your hopes on that because when company goes bankrupt, users end up with nothing. That's why everyone always suggest to hold coins on wallet that you control. When your funds are in their hands, you are never safe.
Besides this, keep in mind that Coinbase states in their ToS that they can block your account and freeze your assets at any time, without giving you an explanation. This is a big red flag for me.