Armchair - they exist perhaps because they probably make initial PPL training simpler, or even possible; 'just do it by rote for now', as the raw stude has no background to 'think about it' rather than to 'follow the checklist'.
It's a bit like teaching 'stall speeds'. How else do you keep a stude safe on the approach other than by the mantra of 'stall speed'?
But there is of course no such thing as 'stall speed', only 'stall angle'.
But it's unrealistic to expect a stude to grasp the principle of stall angles at the beginning of a PPL course (heck, I know some very experienced pilots who haven't grasped it!), so teaching 'stall speeds' is the pragmatic method.
So it is with check lists.
But they should be simple, not multi-page affairs. And most important of all, they should be disposable, ditched out the window just like 'stall speeds', once the pilot has sufficient ability to think about what they are doing rather than doing it by rote.