Qualia are the inside view of sensory data and reward signals.

Think about it from an evolutionary perspective:

Animals that step into a lava flow or forest fire don't reproduce. Eventually some evolve the ability to detect intense heat from a distance, and pain as soon as tissue destruction is imminent. They do not have nor need a general understanding of the dangers of heat, or even conscious awareness that they've stepped on a hot coal.

The pain signal compels them, but that is very low level machinery. It had to continue compelling beings that developed larger and more sophisticated brains that are capable of abstract thought and reasoning. Feeling pain is one of the lowest level parts of the brain telling the higher parts exactly what its going to do in terms that permit no disagreement.

The internal experience has bearing on physical reality right here, because without it you wouldn’t have written about it and caused these words to appear on my screen in physical reality. It affects your thinking, and hence your actions and utterances in the physical word.

For reasons like that, I don’t think that P-zombies are possible.

Internal to what? The brain is not a monolithic thing, it is different parts communicating and interconnecting. When the connection between the halves is cut, the person objectively becomes two people, but still experiences and presents themselves as one. Observing ourselves is just one part of the brain responding to another, or theorizing on past behavior. There is probably no actual introspection going on inside of the human brain, only the perception of one.

There are some evolutionary theories why did qualia("phenomenal awareness") evolved. I don't know much about those, so i can't write about that.