"Most EU countries recognize this". "THe EU understands this"

Umm....have you seen what's happening in most EU countries right now? It ain't pretty.

And you are not traveling in an EU country you are traveling in the USA. Any business can set their own rules such as No shoes No shirt No Vax card no service. So be ready for anything, anywhere. A lot of business have gotten really sick and tired of continually having staff out with covid for 10 to 14 days at a time.

did you have to show the cards?

You don't say specifically where you're going, but you should be prepared to show proof of vax and a photo I.D. to dine indoors, enter theaters, museums, etc. Being prepared is easier than trying to keep up with changing rules. I have taken a photo of the two with my phone, and that has been accepted everywhere (so far). I haven't been asked to present the actual CDC card. Masks are required to enter restaurants, grocery stores, shops, banks, office buildings, etc.

As an aside, some cities are ending the temporary outdoor seating at restaurants that was set up early this year, so reservations will become more essential as demand shifts indoors and/or to restaurants where the outdoor option continues.

Statewide indoor mask mandate in effect tomorrow. Will it be enforced, who knows?

I assume you will not be attending any large indoor events which will also require proof of vaccination.

The restaurant thing will be case by case.

Forget November 8 rules, Gov Gavin just implemented mandatory masks indoors EVERYWHERE indoors (as was done in NYC) from 12/15-1/15! Wear your masks and you should be ok. (Just don't attempt to take your friend to Hawaii -- even with CLEAR digital pass, it is still time consuming, as to avoid long lines upon arrival in HI, you must arrive with a wristband given out at the gate of Hawaiian Airlines, after linking your Health Pass and Vacc Records into State of Hawaii website..... but Maui was worth it! )

Thanks for the update. I saw that development. Given that all of the vineyards and restaurants we booked already required masks that won't be a material change. (i loved Maui when I visited in "ordinary times" but it is so far to travel from the East coast that I may be once and done for HI, sadly!)