Comment by pmontra

You must have a SIM in the laptop at home (that's a "2FA mule") but you can use the WiFi on the phone. That helps also in other scenarios.

The last time I was in Australia I had a dual SIM phone. I put an Australian SIM in the second slot and used it for calls within the country and for data. SMS from my country didn't reach me or cost an absurd amount, can't remember. The point is that I was out of reach of 2FA SMSes and I couldn't use one of my credit cards online. Of course their customer service told me that I could switch my account to my Australian number but that never worked, it's probably a common move in scams and identity thefts. A 2FA mule would have saved me somewhat, as in some remote areas there was only voice, if lucky, and data was so slow to be useless and WiFi doesn't exist in the middle of nowhere.

Anyway, would have I left my primary SIM at home and be unreachable on my way to and from the airport? Probably not.

2FA on SMS should die. Unfortunately it's very convenient for companies. There is little setup and they can send an SMS to any random customer with little friction on customer side. No app to install, nothing.