Learning native programming language compare to cross-platform framework such as Angular

Question

Why would one learn a native programming language such as swift, Java for relevant mobile application development, whereas learning something like angular 5 or react native which allows for cross platform development.

Answer 1

Web applications have disadvantages compared to native apps, some of them are: requires internet access all the time, has limited or has no access to some system features (files, threads ect), IE problems and they’re normally slower.