Lots of info about that here on this forum, but in a nut shell...
While kiteskating under power, the skater is leaning at an angle to the ground away from the kite. Sometimes, I'm able to reach out and touch the
ground without bending at the waist. You can imagine that even though you have 6 inches of clearance in an upright position, there may be only 2-3
inches of clearance while skating with a kite cross wind. Add some bumps or rocks in the surface and the ground clearance is reduced even further.
Therefore, bending the rails would only reduce your under power ground clearance and increase the possibility of touching a rail to the ground and
"skipping out" on the rails.
The only real advantage to lowering the rails is added stability. I address this issue by offsetting the skate boot to the inner leg side of the
rails. Balance is another advantage to using large wheels. Lining up the boot with the axles offers a good combination of balance and clearance.
I only recommend lowering the rails for wheel/tires greater than 16 inches total diameter.