The old World of Tanks Assistant app was never good, but other games out there have apps that are actually convenient these days. Destiny 2 has Destiny Item Manager, World of Warcraft has its Companion app, Rust has Rust+ and it would be great if World of Tanks had something on par with any of these.
Here are some things a good modern mobile app would be useful for.
Collecting timegated resources, like we have in this year's Holiday Ops.
Viewing daily missions with the ability to reroll ones you don't like.
Access garage/clan/friends chat.
Purchasing things from the depot using credits, like consumables when they're on sale, or spend tokens for things like drops.
An app could also be a simple way for WG to send notifications to players regarding news/events/sales that they otherwise might have missed, but this would have to be reserved for actually important news otherwise people would likely turn the notifications off.
