Certainly I completely agree that subs are not "necessary" to enjoy acoustic music, but in my experience they can enhance my enjoyment of it.The problem with these types of discussions is that people prioritize things in different orders.
I'll agree with Learsfool that a very high percentage (but not all) of the sub-augmented systems I've heard over the years sound unnatural to me when playing acoustic music.
Part of that is the nature of recordings while another part is that a living room doesn't have the same acoustics as a concert hall.
Simply put, any system playing recorded music - regardless of cost - is a set of compromises when compared to a live acoustic performance.
However, it is no surprise that some people are very happy with their added sub while others look at it as a complication that may or may not improve the situation.