That’s not true. You can use TestFlight, but you can choose to distribute it elsewhere.
Michał Tuszyński

CodePush for example has made it incredible easy to have multiple versions of my app, and is how I quickly test changes on my device. My last update for Rizer was actually rejected by Apple for using the word “beta” in my Settings page. Apple specifically told me that all Beta builds must go through TestFlight.

I am aware that there are other ways of distributing an app, but it’s unclear at this point if any of them are actually approved.