Good question. Using mail as a metaphor: I would like Apple mail to adopt advanced organizational features equivalent to a desktop client OR allow us to select our default client for that category of app. Frankly, the second option might be better because then Apple could focus on core platform development and leave advanced feature sets for apps to the third-party developers to implement. However, with iOS locked down as it is you can’t get away from Apple Mail of Safari, so for me why have the friction of relying on a certain app when I have to default to the stock one.