Definitely something I didn't know I wanted! Haven't tried it but it looks great. I think you should explicitly say in the description that users will save on cellular data/roaming fees as a main use case.
It's not too surprising that Audi is also affected by the scandal. It makes you wonder if the higher end VW child companies (Lamborghini, Bentley, Bugatti, etc) are affected as well because of the scandal.