I care very deeply about personal responsibility so I don't appreciate the implication that simply because I enjoy Apple providing me ways to minimize my exposure that somehow I rely on that and do nothing else. Apps at this time are forced to be on the Apple store, if/when alt-stores are forced onto the ecosystem I may then have to make choices, as an example, say my bank decides to host their own app because they can, I then have to decide if I will undertake the hassle of my business elsewhere. I'd PREFER not to have that choice forced on me, I enjoy the fact that Apple's ecosystem protects me from needing to have 10+ app store apps, all with my personal info.
Also, if you are debating in good faith, mobile devices have heralded in an unprecedented assault on our privacy, everyone tracks you and collects data, your ISP, your mobile carrier, all your apps and even your device. Looking for ways to minimize this threat is an absolute no-brainer. Now YMMV, if you don't care at all about what all the software you have downloaded over 30+ years has collected and sold about you then good for you, most of those 30+ years would have involved desktop software which has far fewer data points to collect. When it comes to mobile devices and their apps they can, in theory, track our every movement and sell that data, I don't care for that and take whatever steps I can to thwart their efforts.