Slider for 5th wheel hitch, who uses them?

I towed a small 5th wheel with a 2000 Chevy, half-ton, short box and the salesman said I wouldn't need a slider and I didn't. But I bought a newer 2007 Chevy half-ton, short box and I found right away I needed a slider and probably used it once or twice per trip. The 2 trucks seemed the same but something was different. With a short box I would go slider.