I’m not sure what the last reviewer was talking about. We live in Australia and recently travelled to Canada and the USA. Rather than have to go to a supplier’s store and buy a new SIM card, we were able to log in on line. The T mobile deal in the US was amazing. We could buy 5 GB which could be used over 5 months. I think that cost $US10. The cost of the SIM is a once off, not something you have to buy in a store in every county that you go to and you can go through the suppliers to find the option that best suits you.

Don't bother buying the Apple SIM for travelling overseas if you want to buy pre-paid data packages in other countries. Every pre-paid data package comes with its own SIM card, so you don't need the Apple one. It's not that expensive (about AUD8) but it's a total waste of money for use overseas.