It would be really convenient to have the ability to buy Mods, Armor peices, Upgrade Modules, Raid Banners, ect. Though the official Destiny 2 app since you can already purchase bounties through the app but nothing else. Im not always on playing D2 because of work and such so it would be nice if I can load up the app on my device during a break and buy a mod or armor peice that I need for my character without needing to load up the game so when I do play it will be there for me ready to use.