I use Uber irregularly (when I travel). Every one of those notifications has resulted in me uninstalling the app as it reminds me I still have it on my phone since the last time I travelled.
It may juice their stats, but I've definitely installed competitors apps when I need a taxi in a new place as opposed to just using the app I already have installed.
I’m pretty sure this violates Apple’s App Store policies, but they seem to not care. Apple even sometimes abuses their notifications to promote new App Store releases and other Apple services.
Many have said it’s easy to disable non essential push notifications. I find it discussing that even when doing that, companies add new categories and have a default-opt-in.