A Toughbook costs more than a comparable MBP.
I.e. the low-end budget stuff that ain't pretty, may have a whiny fan, but still gets the job done.
For reference, here's a Lenovo G550 for $389:
http://www.newegg.com/Product/Product.aspx?Item=N82E16834146...
The MBP starts at $1199.
So yeah, it is maybe more expensive but I can totally see why you would want that.
(As long as toughbook refers to Panasonic Toughbook brand, if there is a cheap laptop marketed as durable that would make a difference.)
I.e. the low-end budget stuff that ain't pretty, may have a whiny fan, but still gets the job done.