Phew, that's a complicated question! On the one hand, poker can be a fun and strategic game that can help students develop critical thinking skills. But on the other hand, it is a game of chance that can be addictive and cause financial problems.
I think it is important to talk to the teacher and understand their intentions. Do you want to teach them the rules of poker as a mathematical exercise or as a recreational activity? It is also important to consider the age of the students and whether they are prepared to understand the risks associated with gambling.
Ultimately, the decision of whether to allow the teacher to teach poker to the class is yours. Carefully consider all aspects before making a decision.