Creating an app means they have to ensure that said app is compatible with a variety of platforms and operating systems. Even with iOS they have to make it iOS14, 13, 12, and iPad and iPhone compatible. Plus, an iPhone 8 has a much different hardware architecture than an iPhone X or 11 - or any new stuff that comes out.
Android is an entire ball of worms with dozens of active software builds right now in addition to the hardware issues.
Moving it to online only means that they can just update the software in one place and streamline the entire process - unfortunately, at a huge hit to useability.