With respect to an engine fire on takeoff, stopping the aircraft is the priority and the memory items will cause that to happen.
As opposed to what? Are you suggesting that without being taught to stop one is likely continue with the flight??
My experience is if you ask the average PPL who is one year (or even a few months) after their PPL flight test "what would you do if the engine failed at 500 ft after takeoff ?", you would get a long pause with lots of umms and errrs.
You would indeed, I can give you the usual rant; nose down, identify a suitable landing area straight ahead, or 30 degrees left/right, NEVER TURN BACK etc. but this is the general principle, not the gospel. If you asked me the question, and I hmm'd and err'd the reason would likely to be i'm considering the scenario not that I don't have a clue!
The checklist is all well and good and should be followed where possible, but there is alot to be said for the fight or flight instinct - our own mental checklist for survival which we do not need to be taught: "The sh** has hit the fan, lets get the f*** out of this death bucket double quick!
Simples.