Why you should use angular-cli?
A project should have a bundler, regardless of the technology stack. A bundler is software that bundles your application code along with its resources into a minimized, zipped bundle that can be easily deployed on the server (at its most basic form).
There are many bundlers out there, most widely used are Grunt, Gulp and lately, Webpack.
They each take a different approach to fulfill the task at hand - but Webpack really stands out from the crowd.
Read more here.