Mobile technology has made huge advancements in the last 15years, Many mobile work forces simply cannot operate without some level compute power to assist.
Whilst some businesses and OEMs initially chose to use consumer phones and tablets, it was quickly realised that the cost of replacing each of those devices 2-3 times during a standard service life was actually much more expensive than even a fully rugged product.
however, fully rugged can still be cost prohibitive for some applications where perhaps being able submerse the product in 1m of water whilst driving a tank over it was not so important as being able to drop the device off a counter or use it in the rain and it survive.
This is where Semi-Rugged jumps in.
You get a the most important features of fully rugged, such as drop testing, IP ratings and long term support, customisation options and more, but at a lower upfront investment.