Fundamentally, I think poker comes mainly down to statistics. This is especially true online, but I also think the older style of poker is more of an art, and is equally valid as a playstyle, even if it would get dominated by modern poker theory.
I think its 90% of stats and 10% of art. But, you know that "art" part is beaten by AI. That means it's 100% stats. But we human being express it "art" because it's uncanny for human brain.
Poker is a game. Strategy is varied and can be either creative (art) or math based or a mix of both. You can also just click buttons but I don't recommend. The thing is though, even when we are trying to employ a math based strategy, unless we are cheating then it's all our interpretation in the end, and that's pretty creative-- being able to run your yourname.exe at the tables with your own brain and understanding of the game. So... art?
Never though of poker as in art but to be honest, I could see it being a art to the game. While there is a lot to being statistically sound player under many circumstances putting your own spin into the game is an art form.
Both, you have to have an understanding about statistics/probabilities/outs. but also how to play the game (art) bluffing, maintain chip lead, steal blinds, hero calls, good folds, patience, discipline, control the tempo and table.
Online poker in my opinion is a statistic mixed with art. In order to win, it is important to know your opponents and apply clear strategies, the choice of actions is an art. Unpredictability of actions will also put your opponent in an awkward position, and by showing such creativity you can become less readable to him.
Although poker over the years has basically been broken down into a mathematical algorithm what makes the game great and in a sence an art is the players. There’s nothing like the poker community people are great sports you make good friends and there’s never any discrimination people only see green when they get on that felt.