For something like a light urban delivery truck - perfect and will reduce air pollution too. A guy I know in Nelson just bought one for his dry cleaning business. He is doing minimal km and carrying a very light load too.
Range is still an issue for trucks outside city areas. For moving stock or logs or line hauling freight on state highways - forget it. Or you would require swap-out battery units or just swapping traction units (like formula-e).
Trucking companies tend to work their trucks hard, because margins are low so you need volume. A single truck driver is allowed to drive for up to 13 hours in a day - and many do. That equates to a daily range of something like 900km, with GCM of up to 50 Tonnes. Then you need to consider additional power for secondary plant like refrigeration.
BTW addressing grade by improving highways would help by removing some of the heavy braking burden.
If you are serious about reducing trucking pollution, there are pre-existing solutions already in place in N.Z. Rail freight (which will soon be de-electrified :-( ) and sea freight. It costs more to truck freight from Wellington to Piction than ship it from Auckland to Christchurch - capacity is the constraining issue. The sea freight companies got very busy (>100% capacity) during the Kiakora SH1 outage as people realised there has actually a cheaper option that was unaffected by the land-slides. The problem is that most peoples vision is only as wide as their wind-screens.