Because people are rational and can be convinced to abandon notions of value deeply ingrained since childhood because of a nice analogy during a single lecture?
By this logic there are no good analogies because there will always be someone that will refuse to look at the situation differently for whatever reason.
To each their own...it helped me look at lab diamonds differently. I've always assumed they were somehow chemically inferior to the real ones, maybe compromised tensile strength or something.
