You don't run these inside enclosed spaces, because the carbon monoxide would kill you.

It's nowhere near as convenient as gasoline--there's plenty of minding and care required--but during hard times it's much more efficient and convenient than hauling a truck load of stuff by horseback, or walking. A wood gas spark engine runs much more efficiently than an equivalent steam engine, for example.

The difference back then is everything was carbureted and switching over to wood gas was relatively simple. With today's extremely complex fuel injected vehicles it will be a whole different story.

Converting the wood to charcoal before use has been found to be the most reliable method of burning wood by most users, with lowest contamination/fouling risk, although the owner of the http://www.driveonwood.com forum (a guy from Springville, Alabama) runs his truck on straight hardwood and has put many miles on it like that.

When in good tune, a full size pickup truck will go about a mile per pound of wood.

Check out http://www.driveonwood.com to see plenty of examples of both. A wood car or truck can be amazingly practical for any use involving long steady state (i.e. highway driving), not so much for city use.

A tractor can certainly work well on wood gas.

I think it would, the only problem being smaller row crop farmers who would be mostly likely benefit to implement it or want to implement it have been pushed out of agriculture more and more over the decades and struggle to survive at all. Which makes spending time and money on experimental work like this far less likely.

Electrics won’t replace ICE until the range issues in cold weather is figured out.