There is no shortage of markdown-based tools on all platforms. Our org markup options, on the other hand, are very few outside of Emacs. Org markup itself is super versatile and can power lots of use-cases.
It's great to see tools like https://braintool.org built on top of org and thus help spread org markup awareness.
I built two org-powered apps for iOS myself:
There are other great ones out there:
Lastly, a shoutout to Karl Voit who's been driving org markup awareness outside of Emacs with Orgdown https://gitlab.com/publicvoit/orgdown. He's also discussed org markup's strengths at https://karl-voit.at/2017/09/23/orgmode-as-markup-only