You only say this because you have not seen the Nissan app so don't know what "useless" really means!
On a serious note...both apps leave a lot to be desired. Clearly GM and Nissan's strong suits are building cars, not building apps. And that's probably not a bad thing.
At least with Nissan there are some third party apps that while still stuck with the crappy/slow API provided with Nissan actually make the user experience tolerable. Things like auto-updating each hour while charging is detected, and single button press widget to remote start HVAC. I don't know if there are any suitable replacements for the Volt (if there are, please let me know).