Lugging a heavy weight about will certainly suck the juice out of it but a lot of these type of vans are carrying small parcels from Amazon and the like.
You are right braking will not return all the power back to the battery as nothing is 100% efficient but it does extend the range considerably.
The only person who got all his work done by Friday was Robinson Crusoe.
Anything i post over three lines long please assume it is an article lol.