Performance : The performance of the Ionic application is not as good as compared to native mobile applications. However, the performance gap is not noticeable for most of the average users.
Security : The app developed with the Ionic framework may not provide as much security as a native application. For example, if you are developing a financial app, e.g., the app for a bank, the Ionic framework is not recommended.
Limited native functionality : There are some native functions may not be available in the Ionic framework. In such a case, you need to develop the plugin to fulfill that function yourself. However, there are many plugins available to cover most of the native functionalities.
Not good for video game : Ionic framework is not perfect for high-end graphics-dependent applications or video games.
Need for specialists : JavaScript can be tricky to learn. So, there is a need for someone who can not only "do" JS, but also have deep knowledge of advanced libraries and technologies including Angular, Cordova, Ionic, etc.
Early adopter risk : Ionic technology is still in development. It regularly keeps changing its support and standard, and its libraries can be completely rewritten at any time.
