[jp10]

In many situations a weapon system has to be 'sold' to budget committees for approval. A system that can be seen as having multi-situation uses 'sells' better than limited use and designers always pitch their systems as being the perfect fit for the 'next generation of conflicts'.
Medium weight armor deploys faster, can use 'weaker' bridges and less rated roads and often are sold as maneuvering easier in urban settings.
These "cheaper, lighter and 'just as good' systems" are always pictured in a best case scenario when criticized as being limited in a traditional war environment. A system that works within current logistical support is always a good, money saving, selling point.
Case in point:
In the 1980's, the US fielded several Light Infantry Divisions for quick deployment, low-to-medium conflicts. The divisions were TO&E'd not for what they needed but to be moveable in the amount of planes the Air Force said they would be able to provide (500 sorties in 48 hours) as a cost effective advantage.
When criticized during budget debates for not being useful in an all out Warsaw-pact attack in Europe, Army leaders came up with the example of Light Infantry Divisions being deployed to Sweden/Norway to stem a Soviet advance thru Finland and sent one of their Light Divisions to the high range of the Rocky Mountains, in December, to prove to politicians that the % of cold weather casualties by troops in Gortex rain gear and with frozen canteens for 8 days is not too bad compared to more expensive units in fancy cold weather gear.