Good question! Yes with good form the motion can absolutely be safe and healthy for L3/4. The goal is to maintain spinal stability with your core while driving motion through the hips. Above all, listen to your body and gradually progress towards the goal.
Great video Ryan, I have a couple of inflatable boards and a really good electric pump. I've always felt it was a fantastic core workout, and I've needed some inspiration to get back at it! Thanks @Core Balance Training very motivating vid!
