It's a local pollution reduction thing
True, but many warehouses and distribution centers are within populated areas. There are a huge number of distribution centers east of L.A., and they are a significant contributor to particulate pollution in the area. It is bad enough that it is causing an asthma cluster in the area.
While hydrogen-hybrids may not be suitable for long-haul trucking, there are other options using current-gen tech. One proposal is to switch to LNG, which contributes significantly less pollution per mile driven. A number of states have been experimenting with it as a cleaner fuel, especially with the crash in NG prices.