Less "downtime" - equipment taken out in the field is always going to get wet, muddy, or dropped. With a rugged machine that keeps on working your vital work won't be held up when the inevitable happens.

It safeguards your work - once you have devoted your time and resources to gathering data, don't lose it just because the computer gets some water in it or is dropped.

These factors combine to reduce the total cost of ownership of your computer.