I downloaded the app. I can see where it could come in handy for checking for shops while you're out and about, but as for reporting? I wouldn't use it, especially since it says, "If you have shop expenses, they can only be reported via the Shopper Website and not via this app."
Sounds antiquated, just like their website.
If your path dictates you walk through hell, do it as though you own the place. -unknown