A sim card can connect to a limited number of satellites, often limited to a certain geographical region. If a traveler goes to another continent or even another country, then the same service might not work. The cellphone might still be able to make calls, but it might have to transfer through a string of satellites. Worse, wifi access might be slow or nonexistent.
This situation can be solved with a global Wifi pass type of card. This is basically a type of sim card that is able to access a broad number of satellites and regular internet connections. The service covers both roaming internet as well as bypasses normal password entries in a variety of wifi hubs. This does not mean a phone with a global pass will be able to access all wifi, but it can access many publicly available ones.
All of this is possible because of the keys on the sim card itself as well as the passwords and arrangements stored in the app that goes along with the service. Between the sim card and the app, it is possible to access countless wireless services while on the move. This is especially true in airports and major hotels where such collaborative deals are common.
It is great not to have to find and enter a password in a foreign port or establishment. Obtaining the password manually might mean having to pay an extra fee. It might also mean having to ask questions in the native language and then having to insert the password using a portal in a foreign language. While this is doable, it is best just to have a one time expense and then be able to logon in many, many places.
A global wifi pass can be compatible with many devices. A laptop with a Mac system or a Windows system might be able to use it. On top of this, a global pass is like a VIP ticket. The service provided might be vastly superior to what is available to more economy-minded patrons. This means that the pass might grant access to higher wireless speeds. The pass might go straight through a satellite experiencing a jam of traffic.
It is also a single device and application that keeps personal information while accessing all these different wifi. The app might even bypass regular service and go through a dedicated proxy. This just means better internet that is familiar to the customer in every port of call.