How come internet sweepstakes casino games are a legal form of gambiling in NC?

I thought Vegas was the only place where you can legally gamble? In my state of NC, we have these Internet centers, where you go inside and you can sit at a computer and play instant reveal and pre reveal casino games. They have a machine where you can put money into your account and log in using your drivers license number, and than play the casino games. You can bet anywhere from 25 cents to 6 dollars on most of the games, but it's hard to win on them. They even give you 100 sweepstakes entries for free every day, which is like a free dollar. I just use the free dollar and have been going to them for a couple of months, and never put money in the machine to gamble, I just use the free dollar they give you each day. They sell sodas and snacks their too, and for every dollar you win, or use, it adds internet time, so you can surf the internet. If you win 6 dollars off of your free dollar a day, that adds a lot of free internet time to search the internet. I know gambiling is pretty much illegal in most states besides Las Vegas, but how is this form of gambiling legall? Recently, a month ago, all sweepstake centers in NC shut down for a week because they had to rearrange some stuff (including video poker machines at places like truck stops) because something was breaking the regulations, but it still looks the same to me, don't quite know what they had to change? I don't have a problem with it, but how is this form of gambiling legal and how do you get away with this form of gambiling when the only state that pretty much is legal is in Las Vegas. Well, in Cherokee, NC, they have real casinos and not Internet Sweepstakes centers. I live in the Piedmont Triad Region of NC. I thought gambiling was only allowed in vegas, just wondering?