Apple’s iOS 12 is already installed on over 50 percent of actively-used iOS devices (iPhones and iPads): This is why it matters:
You get new apps first, and old ones get better faster
There are real advantages to developing for mobile devices. The market is massive and massively diverse. There are viable opportunities to create niche interest solutions.
Development takes time, of course: and one thing that sucks so much time and resources from small development teams is the need to test software against multiple hardware and software configurations.