Yes heat is a by-product of friction.

In the case of graphite, however, friction manually removes the graphite without relying on the heat it happens to generate. So he assumed erasable ink had something in it that made it behave more like graphite and made it possible to remove with abrasion.

It actually turns out that there is something in the ink that reacts to the heat instead of making it more susceptible to abrasion like he assumed, which was new information to him.

The name being Frixion does not make this obvious, nor does the fact that friction generates heat (which everybody already knows so you are also entirely unhelpful).

I’m not being sensitive, there’s just a part of my brain that feels the need to explain why stupid things people say are stupid.