Only exception I found is bacon. Get one of those big metal baking sheets with 1-2" sides, and line it with baking paper. Lay your strips of bacon down, without them touching, and put in the oven. Set to around 425 and your bacon should be done in about 10-15 minutes once the preheat beep goes off. You figure out the time that works with your oven and bacon thickness. Memory is a little fuzzy.

I read that somewhere once and it comes out way better. Otherwise the top side never gets browned and then you try flipping them to make up for it and it sucks. This way you don't have to mess with it and the paper absorbs most of the grease. Easy to clean up.

Am I the only one assuming they refer to the step at the start because the recipe will always take longer so I'd rather just wait for it to heat rather than set right away?

There are only few things that are really sensitive towards low temperatures - cookie doughs, soufflé and maybe bread. For any other food preheating the oven ia just a waste of energy.
Food companies only write it on the instructions because the time the food needs in the oven is not valid when they have to count in the speed your oven needs to heat up.

Preheat your pizza or else

I feel the same way, but only for pre-cooked frozen foods. Not for baking, and nice dishes

that is so fetch