Wouldn't you at least consider this a useful use case: Purchase a flight online on a website, but then get a push notification if there is a flight change? Why should we force a user to download an app to support that use case.
>>hn_thr+(OP)
Why not just use SMS instead? It's timely, and it works even if the target device is in an overcrowded airport and can't get mobile data.
>>jachee+02
For privacy reasons, some users would prefer not to give phone numbers. From a provider perspective, sms would become a significant cost if you're sending millions of texts, while push is essentially free.