Yes, Tuist is now available on the App Store 
(see full blog post here)
We are strong believers in leveraging the platforms we build for as much as we can and dogfooding our work to have strong empathy for anyone using our platform. While in some cases, it means we need to juggle multiple pieces (be it our CLI, server or the macOS app), we strongly believe this is the best way to build software for developers.
With Tuist Previews, an opportunity has opened up for us to meaningfully improve the Tuist platform by providing a native experience to access and run your previews.
The app is a foundation for us to build upon new native experiences, so stay tuned for more 
Oh, and the code is of course fully open-source – so if you’d like to contribute, let us know and we can help you get started.
If you have feedback or ideas for the app, let us know below 