DST GO Package

Today, or rather, yesterday, I subscribed to the GO monthly plan. That was the only plan that made sense to me as I already had enough computers. Also got myself one of their modems. The only thing that I felt was ludicrous was the plans for the supplementary cards. Yeah. Ridiculous is probably a better word. Initially, I thought that these cards were add-ons designed to allow one account to share the bandwidth with the supplementary cards holders.. maybe with a small additional fee on top of the plan. Ok.. I was wrong. OMG. $70+ dollars per month per supplementary card? Are they kidding? Just to share the bandwidth? Why not just get your supplementary holders their own plans with their own bandwidth? Sorry, I'm pretty much one to speak my mind and my mind says that is just a stupid product. No sane customer with any sense would subscribe to it. It just doesnt make any dollar sense.
Here is a quick and simple equation for those who came out with this...
Scenario A:
Subscriber - $78 / mth = 3.5mbit
Supplementary - $73 on top = SHARING same 3.5mbit
so $151+ = 3.5mbit
Scenario B:
Subscriber - $78 / mth @ 3.5mbit
Supplementary - $78 /mth @ 3.5mbit
so $156 = 7mbit!
Why even bother coming out with a plan like that? Is there logic in that?
Dont get angry at this. I was educated as a global marketer. What we were taught were to create packages that produced benefits / value for the customer inducing further purchases and ultimately sales revenues. Is there something I missed?