For web developers, time is money, and no one wants to spend their precious time on a complicated installation and configuration process.
Installation is handled using Composer. If you want a description of the installation process, Sitepoint recently published a great article here. I tend to favor using the basic application template, even when my site has a separate front- and backend component. Instead, I opt to use a Module for the backend portion of my sites. (Yii Modules are best described as mini-applications which reside inside your main application).