The Difference is if the machine in the shop goes down they do not loose the Planting/harvest window before they loose a years production due to weather.

If your planter/ tractor/ harvestor goes down for a week at the wrong time in the wrong year you might loose 10-90% of your crop.  They loose the 1 machine for a week.

 I have seen what not having farming done on time costs. Sometimes it makes or breaks your year.  I can't control the weather, but I can control the machinery somewhat.