I wonder if there is an element of money making here.
Damned right there is. Depending how flights are charged, the money can get taken out of your savings as soon as the Master Switch is actuated; while in other aircraft types the money only flows once an engine is started.
Lets take the latter. Engine starting and oil pressure switch starts the money coming from your savings. After Start check list Challenge and Response depending on how many superfluous items involved could take at least two minutes. At $300 per hour hiring rate that is $5 a minute or $10 just to read the checklist. More if the instructor is a talkative type.
At the holding point, carry out before run up checklist then the actual run up checklist followed by before take off checklist reading. Potential for five minutes of challenge and response which costs another $25.
Airborne no charge for checklist reading. Shut down checklist reading at end of flight costs one minute another $5. Total charge for reading checklists at least $40. The lengthier the checklist designed by the flying school, the more challenge and responses and more of your money flows into the flying school coffers. Have flying schools never heard of the left to right scan for before start, after start, pre-run up etc?
Paper Check list reading in the air means heads down in the circuit when eyes should be outside and head swivelling