I am afraid you either read it too fast, or you are "blind".

I think you read it backward regarding Chase Visa Signature. BTW, whether it is Chase Visa Signature, or Chase regular Visa, or Visa in general, if it provides rental car insurance at all, it is governed by the same rules you can find it on Visa.com. Someone has posted it already.

Read again, under How does this benefit apply?

It is very clearly stated

outside your country of residence or if you do not have automobile insurance, this benefit is primary in those countries where it is available, and in that case, you do not have to claim payment from any other source of insurance before receiving the benefits.

The paragraph before it related to "Within your country of residence" - which is again clearly stated how it work - it is a secondary AFTER your primary insurance - be it your own policy or your employer's policy. AFTER you claim the benefit with your own insurance first, then Visa benefit would pay what the primary does not pay for items considered covered - generally it is the deductible. It will, however, become Primary if you dont have any comprehensive insurance, only liability insurance on your car, or you dont have car insurance at all.

Read your SPG AMEX agreement again under Description of Coverage, at the end of the paragraph.

*Other than those located in Australia, Ireland, Israel, Italy, Jamaica, and New Zealand".

Read your MC paperwork again. They exclude the same countries as AMEX does.

I cannot imagine how you can miss so much important information on each of the agreements. It probably is better for you to simply buy the insurance from rental car company, as you obviously do not seem to have a grasp on the concept, and able to navigate the fine prints of the documents. You would have a hard time tackle the red tape should you really need to invoke the benefits.

Italy is NOT covered by AMEX, nor MC.