Originally Posted by NickB

If you look under policies on the US website, it will tell you how much a day CDW/LDW is and you will see that it is normally quite expensive for a two-week rental.
Some US car rental companies will force you to take CDW/LDW anyway unless you have primary liability insurance elsewhere. This is OK for US credit card holders, as US credit cards normally provide that, but European credit cards normally don't. This is why US sites do not normally include CDW as many US renters do not need it.
Some Amex travel insurance policies do cover CDW/SLI but not all. Natwest also used to sell standalone CDW cover for a year, which would work out cheaper for frequent visitors to the US. Don't know whether they still do.