How Important is Dynamic Headroom?

I recently bought a B&K Reference 200.2. I liked how it sounded at the store, and, in regard to specs, I was impressed with its high damping factor (450). Also, it has 225 wpc into 8 ohms (375 wpc into 4 ohms). Hence, everything seemed fine.

I read the owner's manual, and it lists the unit's dynamic headroom as 1.2 db. I did a brief search of other similarly priced units, and 1.2 db would seem to be about average (or perhaps on the low side?). Anyway, how significant is this?

Thanks.