I was using my phone to try to find a product in my local store, but I was getting dozens of Marketplace items and couldn't figure out any way to filter to just Best Buy items. On the main website, it's super-easy -- a simple tab for Best Buy Items vs. Marketplace Items.
This seems even more important on the mobile app, since someone is very likely to be looking for something in-store.
If that feature isn't there, it needs to be added. If it is there, it needs to be made MUCH easier to find.