Cost of development
On the excellent Oddly Influenced podcast, Brian Marick was talking to Glenn Vanderburg about engineering.
My big take-away was engineers build models to simulate real materials or situations because it’s cheaper and less risky than building the real thing at 1:1 scale and getting it wrong.
In software (UX) we create and test prototypes because it’s cheaper than getting real people to use the real thing and finding out it’s wrong.