The main problem with Option B is the potential for bad/inconsistent app download experiences. Many companies may cheap out on binary hosting and have very slow

The main problem with Option B is the potential for bad/inconsistent app download experiences. Many companies may cheap out on binary hosting and have very slow or broken downloads (especially in certain countries), which results in a kind of random "never know if this will work well" patchy UX for iOS/Android users at large. This isn't an insurmountable problem of course. Perhaps Apple/Google could charge fixed bandwidth rates and host it themselves, or they could contractually set SLA requirements that could be verified regularly with an uptime service.