I haven't worked with hot water so I haven't experienced those benefits. But working with hose that is like coils of wire in winter makes cleaning a little less pleasant.
We need an on demand heater to work with hot water, but for those who have taken the electric heating element route to warm water, I think a more safe way is a lower rated element. They also have the added benefit of using that water in the tank as a big heat source which should keep the van from freezing up on cold nights, probably better than me having a frost controlled heater.
Personally I would prefer the diesel heater route, but many small one man cleaners have done quite well with their gas heaters. How safe some of these installations are is another question, and as Archer is an employer, he has a duty of care with regard to his employees. In his case, more can go wrong with a gas setup IMHO.