Apple’s focus on developing the Swift language supports the idea of Swift having longevity within the Apple ecosystem. Building applications natively supports access to device hardware. In addition, natively building applications enables developers to take advantage of incorporating the latest frameworks as well as the latest updates to previous frameworks, sooner.
Ionic being a third party framework brings up a few questions to ponder before starting a project with Ionic. How much longer will Ionic exist as a company? Will Ionic continue to update their framework to support the latest development made to Apple’s platforms? How much longer will Apple continue to support apps built with third party frameworks?
Is this app being built to test a business concept or is it being built for the longevity of a confirmed business concept?
Applications with web-similar functionality can easily leverage either choice, with longevity only coming to question with Ionic. It comes down to the product, functionality/hardware requirements, anticipated longevity, and risk assumption.