What can you expect for medical coverage traveling internationally with health insurance bought in the US, especially Medicare?

We've gone across the pond 3 times since we've been old, and no, from everything we've been told, Medicare is simply a pretty card in your billfold. No coverage. That's the info from 3 different sources as we've prepped for trips. Yes, we've bought travel insurance each time. There are several companies out there. Our current policy is thru LeisureCare Travel Protection. I hope we don't have to find out whether it's good or not. 

As said, Medicare won't cover you but you could get an add on policy like this from Blue Cross Blue Shield if you had them.   Edit, maybe you don't even need to be a BCBS policy holder, might be for anyone.

. https://geobluetravelinsurance.com/

This is right from the Medicare.gov website:

Extra benefits - not covered by Medicare

Foreign travel emergency First: $250

Then: 20% and amounts over the $50,000 lifetime maximum

Footnote
Note: Policies may include additional benefits not listed here. Contact the company to find out what additional benefits, if any, it offers.

This is for Plan G, which is one of the most comprehensive plans (similar to Plan F).