I was taught the throttle for airspeed, pitch (attitude) for altitude/ROD methode in my initial training on powered aircraft. Perhaps because it was a training which had the goal to make you good in flying jets. It was quite a change for me because i started flying on gliders. But it worked very well and it's the methode i fly my 737 nowadays.
And in the 737 you can control ROD with the throttle (pitch-up/down moment on throttle-movement), but it's far too slow for a good approach or even level off.
Just my 0.02 EUR, Denti