Coin flipping is a canonical example that has historical, theoretical, and practical relevance--it's definitely a bit much to call it "extremely bad & misleading". Mathematically idealized coins do behave in this way, because you have the freedom to define the probability of the events however you like (so long as you do not violate the axioms of probability).
Also, there are lots of (abstract) mathematical nuances to explore around coin flipping once you get into stochastic processes (there are special aspects of Bernoulli RVs with p=0.5).
Besides, sometimes an imperfect example is a better one--it can stimulate thought and discussion about how well concepts--like modeling a coin flip with a random variable--map to the real world.
The chance part of the coin flipping comes from the inability of the human hand to adjust the speed of flipping exactly the same everytime. Is this correct? A coin flipped by a robot should land the same side always.
Also, there are lots of (abstract) mathematical nuances to explore around coin flipping once you get into stochastic processes (there are special aspects of Bernoulli RVs with p=0.5).
Besides, sometimes an imperfect example is a better one--it can stimulate thought and discussion about how well concepts--like modeling a coin flip with a random variable--map to the real world.