I’m guessing the main (technical) hang-up is that it messes really badly with one of the most distinctive things about iPads vs other devices, which is extremely low time-to-interactive from any sleep state. Device been sitting on your desk untouched for three weeks? Pick it up and it’s ready to go almost before you are, and still with a useful amount of battery left (offer void for cellular models).
Not my experience. I have iPad Pro and I only use it for workouts. It sits on my workout machine and once or twice a week I try to watch a ~45 min episode while doing cardio. It’s always dead and needs constant charging. Never last more than 3 days without needing charging.