LA Times article has a quote that supports your view:
"If I’m enjoying the mileage and the torque I’m getting, I might wonder whether this 'fix' will negatively impact my car’s performance," Brauer said. "I'm going to get to that right after I rearrange my sock drawer."
Interesting that this quote appears to have been deleted in a later version of the article.
The issue came to light initially after a study from researchers in West Virginia found that a 2012 Jetta and a 2013 Passat had substantially higher than reported emissions in use. VW denied that there was anything wrong with its models' emissions control systems and asserted that there were technical issues with the individual test cars. Still, CARB and the EPA launched investigations. VW issued a voluntary recall of affected models at the end of 2014, but CARB and the EPA were not able to find noticeably different results in recalled cars.
After the EPA and CARB made it clear that they would not certify VW’s 2016 diesel vehicles unless the company could explain the anomaly and make sure it wouldn’t reoccur, VW admitted to having installed the defeat devices.
VW realized they wouldn't be able to get away with denying wrongdoing (with criminal consequences), so they admitted it.
Germany is a small country, they run their diesels there and do not have a smog problem. I believe that the EPA emission standards here, are driven by the oil companies, who do not want to see a 60 mpg vehicle on our shores. It would cut into their profits.