These days I witness poker players brandishing the phrase “GTO poker” like it's a selfie stick at the beach. Sure, it’s a sexy idea — to apply “optimal theory” to your game — but there’s an essential aspect to the idea that most players miss.
While pure game theory optimal solutions (i.e., equilibria) are characterized by two players playing perfectly, GTO can still be used to analyze spots where your opponent is far from perfect. In fact, since the vast majority of us are imperfect (a.k.a. human) players, arguably the real power of GTO analysis is how it can improve your exploitative play.