A program that grants points for using Bing search, which users can redeem for gift cards, sweepstakes entries, or charitable donations.
Hi,
While having the Bing app on your mobile device can offer some benefits, I don't believe it is a requirement based on the instructions in the Bing Star Bonus "How it works" guide. You can continue earning up to 2,100 points as long as you maintain your Gold membership. To keep your Gold status, you only need to complete two Level Up activities, which you can find in this section. Of course, activities vary per region so check what's available for your account.
https://rewards.bing.com/earn?section=levelup#:~:text=in%3A%200/1-,Level%20up%20activities,-1/2
Bing Star Bonus How It Works guide:
You might also want to check these articles:
https://support.microsoft.com/accounts-billing/rewards/getting-the-most-out-of-microsoft-rewards
https://support.microsoft.com/accounts-billing/rewards/limiting-your-searches-in-microsoft-rewards