I believe that’s only half true - read this thread for more information.
As you can see, view caching in Ionic only applies to views you’ve visited - it’s not a “pre-cache” solution.
To use pre-caching, you can use a solution like Angular Template Cache, as explained in the thread.
Coincidentally I’ve just completed my new Ionic Starter App which includes an optimized gulp.js file that supports Angular Template Cache:
You can use this gulp file (or a variant of it) to perform a production build that includes template caching.
(blogged about it here)