The forward position grants you the total control of your bike. Back wheel glued to the ground and front wheel not jumping up. Your back will thank you because will be less stressed and less curved.
In very steep downhills the down and backward position helps to better drive your bike, and you can go easily out of the saddle. Infact the saddle moves down up to 105mm, like in standard xc-trail droppers. If you have to move behind your saddle, this will remain out of your movements.
On jumps, max freedom of movement, the saddle is not obstructing and will allow you to change the center of mass position very easily.