Arguably the largest single barrier to Zwift entry is on the computing side of things: many people do not have powerful enough computers to run Zwift smoothly, or at all. (Zwift requires Windows 7 64bit or higher or macOS 10.7 or higher, plus 4GB of memory and a fairly beefy graphics card.)
This move opens Zwift up to a massive new audience of folks who aren’t willing to make a huge investment in indoor training but already have a compatible iDevice and an indoor trainer. No ANT+ dongle needed: just pair your trainer to your iDevice and go!