It's fast to install dependency anytime I want, and I like the caching mechanics it has to give the fast download experience.

The big advantage of Yarn is the speed over NPM when using React Native. We are dabbling in React Native and the great thing between Yarn and NPM is the speed of the dependencies in Yarn. If you are going to dabble in React Native and are trying to figure out if you should choose between Yarn or NPM. In my experience Yarn works great in development and has fewer vulnerabilities issues versus NPM.

Yarn makes it easy to combine all of our dependencies into one simple place. Before we used to use npm and bower to manage the different source js libraries, but yarn simplifies this process. It also allows us to do pre and post install scripts so that we don't have to use something like gulp.