In the days of tail-wheel military types (Spitfires, Typhoons, Mustangs etc) wheels up forced landings were recommended. That was because of the tendency of tail wheel aircraft to tip over nose first when brakes applied. There were many accidents where this happened and the pilot was trapped upside down in the cockpit often with tragic consequences if the aircraft caught fire.
With the USAF introduction of the Sabre jet fighter with nose wheel configuration, the much higher touch down speed of jet fighters meant a wheels up forced landing was severe on the pilots spine due to the energy being absorbed by the bottom of the fuselage directly on the pilots spine.
This led to wheels down being the preferred method of a dead stick landing. Even the landing gear being torn off on impact meant excess energy was dissipated and less chance of pilot injury. Tricycle landing gear aircraft have much less chance of tipping over than a tail wheel type.
Depending on the surface it also meant that brakes could be used to shorten the ground roll. All this was evident 70 years ago and wheels down forced landings for nosewheel types (unless ditching) have become SOP since those days.