We ship and receive agriculture equipment like that all of the time. The crate offers some protection to the contents, but it's main purpose is to make the oddly shaped commodity easily stacked and moved/loaded/unloaded/etc. Plywood is an extra expense, requires more time to apply and remove and makes it much more difficult to inspect the equipment. And to those who may be curious, many of the items we deal in are much more expensive than the MGA's shown above, even with inflation factored in. So, It doesn't really surprise me too much to see those cars in crates like that.
I was harkening back to these: When jeeps were crated for the war effort, which of course made them easier to ship by rail, put in a ship's hold, and put on the bed of a CCKW.