After seeing a question about this recently, I checked my prepaid account and I now have this in my add-ons too. The fine print says something about "session" and verbiage about being connected to a particular cell site, which I think is the disclaimer that one's data speeds may still be slower than those on postpaid. Does this mean it's a one-time use thing which for $10, you can ignore your typical data allotment for 24 hours only, or whatever the time frame is for a "session"?
Would be better to just upgrade your plan to an unlimited one if you truly want to go unlimited if that's the case.