Depends too on the simulator instructor's previous background. So one instructor says its OK to de-select speed and leave the AT armed. Another says just do what the Boeing books say. There are no crashes either way so the student decides on the safety of contraception - i.e.de-selects speed just in case so he won't stall on final.
Conflicting information during training is of course a big no no. I flew the 737 classic and NG in airlines that used the ARM function, consequently the FCOM was adapted as well as the training to reflect that, the boeing warning was not contained in the FCOM anymore and every trainer advised us to use the ARM mode, and we were trained in its behaviour. Worked like a charm and had some positive and negative sides. In weather with strong gusts we tended to switch the AT off completely as intermittend autothrust activation above bug speed happened.
We didn't see it as a crutch, but rather as a safety device, and funnily enough boeing did agree on its frequent audits.