@trinsec the magic of reading is exactly that. You can stop, slow down if you need or rush through a less interesting passage. None of that is available when someone sets the reading pace for you.
As you say, it is exactly as with movies. It works great with fiction, as it is more immersive, but also if you feel tired and need more time to process the information there’s no way to slow down the pace except pausing every now and then or going back 15/30 seconds.