plenty of reasons. the difference between android and apple is pretty stark, and they both have merit but dont dismiss the arguments against the more closed ecosystem
the apple method allows a really easy UX for every single purchase and install on ios; if you allow a developer to decide that they’re only releasing on NewOpenAppStore, a user has to go ahead and somehow install that, which is a mess. apple don’t want that, because it just looks bad for the whole ecosystem
the security implications are obvious; if a user wants a pirated app, they will follow the “technical instructions” to click through menus and allow 3rd party installs so they can download their package from legitnotmalware.com
there are plenty more in the same kinda thinking, but overall they are different approaches but the walled garden should not be dismissed. you can argue that the down sides outweigh the upsides, but don’t just dismiss anyone that decides the upsides are worth it as “apple apologists” in an effort to condescend and shut down conversation