My chargeback was simple. I booked a flight. I have documentation that the flight was cancelled. I have documentation that the airline declined to refund. I can show that I have reasonably attempted to contact Expedia without success. That was enough - in fact, they didn't even ask me to send any of this evidence to them.
"No reason or practical way to take it" is a different scenario. The reason chargebacks work is because the service was not delivered. If the flight does operate, then I don't believe you have (or even should have) any recourse. This isn't personal - I, too, have an intra-EU flight from IT to CH. I won't be on it, though, because I can't currently get to IT in the first place. If the flight operates as scheduled, I fully expect to lose my $100 ticket or accept a credit that I doubt I'll ever be able to use.
I would think that if Americans are barred from taking the flight, you would get your money back from the credit card company. But we'll see.
Meanwhile, for folks who have received an Expedia refund receipt -- after successfully convincing them to give you a refund -- how long has it taken for the money to actually flow back to your credit card? My receipt for my cancelled Air Canada flights was issued a week ago and still no actual refund. They must be slow-walking the process because it's never taken me this long to receive a merchant refund. I already have the temporary chargeback credit from Citi so I don't really care (I would think it would be impossible for Expedia to now argue I'm not entitled to a refund!), but I would like this refund process to be completed.