Since this is a US dominant site, an important point to realize is that Americans have never had a real SIM card experience like the rest of the world has. 1)

Since this is a US dominant site, an important point to realize is that Americans have never had a real SIM card experience like the rest of the world has. 1) Until LTE, the US had 50% CDMA and 50% GSM networks, with the former not even supporting SIM cards. 2) The US has always had a miserable carrier locked cell phone experience, unlike most of the RoW where buying unlocked phones was the norm. The combination of the above meant that Americans have never experienced the brilliance of being able to switch SIM cards easily (or have multiple SIM cards), whether to keep different phone numbers/accounts, travel abroad, use a temporary phone, have phones lying around for visitors to use, keeping backup phones, etc. Also, SIM cards made hacking around with cell phones super easy. MS had an embedded Windows OS that worked perfectly with SIM card readers that made it possible to do all sorts of cool stuff with SIM cards (I'm sure there were Linux equivalents but I wasn't as into Linux at the time).