rationalskepticism.org

From your Wiki link, Pebble:

The hard problem of consciousness is the problem of explaining how and why we have qualia or phenomenal experiences—how sensations acquire characteristics, such as colors and tastes.[1]

I don't know about the "how", but the "why" is fairly simple: to simplify the huge mass of sensory data flooding into the brain throughout the waking day. Without that simplification, the PFC (the decision-making part of the brain) would be overwhelmed by a vast array of meaningless signals.

The existence of a "hard problem" is controversial and has been disputed by philosophers such as Daniel Dennett[4] and cognitive neuroscientists such as Stanislas Dehaene.[5] Clinical neurologist and skeptic Steven Novella has dismissed it as "the hard non-problem".[6]

I'm inclined to agree with Novella on that!