So if you are halfway up a climb, stall it out, then what's next?
Clutch, brake, put it in reverse, start engine, slowly let off both brake and clutch to allow tranny to ease you back down the hill, no brakes?
The idea works up and down hill. I definitely let it stall on the down hill since engine braking is much more effective than foot braking.
Think of it this way, if the engine is off and the truck is in gear and the hill is steep enough for the truck to turn the engine in gear, the tires are at least moving and providing resistance and traction and you can further control the rate of decent with the brakes. If you are in neutral or have the clutch engaged, your tires will just skid and the only thing controlling your rate of decent is the brake.
Nothing will have you s***ting your pants quicker than a sudden, uncontrolled decent.