If you're traveling across Europe, get a local SIM or eSIM. Under EU law, your eSIM/SIM subscription is valid in any EU country, and most providers will also cover non-EU countries like the UK, Norway, Iceland, Switzerland, Liechtenstein, Monaco, and San Marino.
Europeans can’t comprehend that you can live in nyc, take a 5-6 hours flight to San Francisco and you’re in the same country and don’t need to do anything about your phone. No extra charge for service.
In Europe you drive 10 min from Austria to Germany to buy cheaper groceries and you have to avoid using your phone because you’ll get extra charges as it’s another country and another cell provider.
That’s why euros use WhatsApp.
Most communications in the U.S. even far away in another state, don’t cost you more.