Hyper extensions are one of the most debated, and perhaps (when done incorrectly) damaging exercises on the lower back. The movement can be ok when done statically, or when done with a shorter ROM and a neutral spine. The problem is, most people do them going from a large degree of spinal flexion to spinal hyperextension. Then, they add on weight and its just painful to watch.
If you really want to technically remove lower back fat...theres always cryolipolysis.
Br