You will lose bundling functionality when uninstalling the app as the theme app blocks will automatically be removed.
Bundle products will not be deleted automatically, but they will no longer function correctly.
When uninstalling, and reinstalling, your existing bundles will no longer work.
Shopify disconnects existing bundle products from the Biscuits app, and cannot 'reconnect' them during reinstallation
Only uninstall the app if you're 100% sure you don't need your bundle products and their settings anymore