Have been thinking of getting hold of a power meter pedal for our e-bike (mainly used for double trailer towing, but surprisingly favoured for child-free journeys) to see how the actual wattage on our travels compares to pre-e-bike.
Indisputably it is less exercise on a given journey than riding it without a motor.
However I would agree that we use the car significantly less, now there is a semi-speedy bike option that can be non-sweaty. So total calories burned might well be more.
What is a shame is the speed cut-out of only 15mph. You can pedal faster (a lot faster in my case) but with an upright riding position and twice the weight of bike, it is not sustainable.
Since I'm not as comfortable in traffic at only 15mph I ride the canal towpath to work and back when I'm on the e-bike. A lot more people try and overtake you in a grim way at 15mph than 20mph+ in my experience.
You can buy faster road legal e-bikes. Unfortunately they come with legal restrictions including not legally use a child seat or trailer, nor go in any cycle lanes / towpath / railway paths etc. And you have to wear a motorcycle certified helmet. So it's like sort of awesome but just a bit too restricted to be mass-modal shift kind of transformational.