The sims from the ST web sight will work the same way, you will need to use the APN settings that come with your sim.
The directions given above appear to be those that were around when the only option for a ST iPhone or android involved purchasing one of the ST Nokia's from Walmart.
Not that ST is selling the AT&T and T Mobile sims people can do the same thing with then at a fraction of the cost.
My work phone is a Nokia to Android swap and my personal phone is a ST sim card on Android.
Both work well except that outside of Saint Louis my data on the TM phone drops off to very slow to nothing. The other phone is on the ST/AT&T card and has far better coverage.
In short, yes you can buy the ST sim and do the same thing.