Poker as we know it today was believed to be first played on the New Orleans steamboats in the early 1800's.
It became the all-American game. Video poker was first introduced in Las Vegas in the mid 1970's and had luke-warm reviews due to the limited payouts. Later when the payouts improved, it became much more popular amongst players.
It has become so popular now that it's one of the hottest games in casinos not only because it is fun and easy to play but also because of the player advantage.