The sound our speakers reproduce and the sound we hear can be two different things.
Because this is so important we have designed our speaker frequency response to be flat - this is because we want our speakers to deliver sound exactly the way it was originally produced.
Think of it this way, the difference in attending a live music event and the same event recorded. The sound you are hearing live and the sound that is actual is different because our own hearing, in this situation, will not have a flat frequency response.
But the sound that is occurring and that recorded will be very similar, and this is important.
When you listen to our speakers we want them to accurately reproduce the recording i.e the actual sound generated. Then we can enjoy the music as if we heard it live.
The fact that our ears do not have "flat frequency" responses does still means there is need for speakers that have this ability.
The best sound possible is always the target