Today web and mobile push notifications are a very effective marketing channel and can be used for different purposes and different products. You can easily promote your mobile app via push notifications if you launch your campaign the right way. Check this article if you’re interested in implementing push notifications to your marketing strategy:
https://esputnik.com/en/blog/5-advantages-mobile-push-notifications-marketing-channel
https://esputnik.com/en/blog/why-and-how-use-web-push-notifications-your-business-advantage