Have been a sound design ambassador myself for sometime, it was refreshing to read some perspective on it from a big company perspective. So if you dont believe me read medium article from the Facebook Sound Design Director, Will Littlejohn :)

https://medium.com/facebook-design/how-to-enhance-mobile-interactions-with-sound-design-3c3b30e98177
You can also check the sound experiences I designed, for home appliances company Arcelik here:
Sound Interface for Arcelik A la Chef Oven
Key points of interface has been determined with user scenario. Main points of interface has reinforced with sound feedback in order to warn, highlight attention or information. Created sound files shared with the R&D team, implemented sound designs were tested on the working prototype and confirmed. Sounds samples produced with GarageBand.