As a lad I had a moped, and you could not have cycled that far as far too low geared, a Honda P50 the pedals were used to start it and for steep hills only, and the 80 miles I would ride Shotton to Tywyn I could not consider doing on a push bike and work when I had arrived.
The wife's electric bike is very different, one it is slower the gears mean 18 MPH is about the fastest you can petal it, although free wheel down hill had 31 MPH, and two you have to pedal it can not be used any other way, and with assist off it is still usable.
So typical trip Shotton to Bryn-y-baal I would do on a normal bike in one hour 20 minutes, most of the time 4 MPH as up hill, and on arrival I am good for nothing, electric same route 45 minutes, and I can mow lawn when I arrive, the reverse journey same time both bikes and around same energy used.
Now Shotton to Chester and back, on the flat, very little in it between electric and standard unless a head wind, and in the main the electric does not assist as over cut off speed. I note the battery hardly is discharged after that route, but to Bryn-y-baal I have used a 1/4 of the battery, for just 7 miles.
At 250 watt on the Wirral cycle tracks I am not far behind my wife, and up the hills only doing 6 to 8 MPH not charging up at 15.5 MPH, it still needs some effort, but means I am going fast enough to balance. And I do when I have tried it switch off the assist for flat and down hill sections. I am aware the battery is 400 Wh and once flat that's it.