Imagine having to reinstall the operating system of a PC for fixing a major instability or software issue.
No need to imagine, it likely happened to you or a family member whose PC you take care of. The process is laborious and time consuming as it takes hours to back up the data, reinstall the operating system, restore the data, reinstall the software, and configure it.
Compare this with a powerwash, the Chrome OS factory reset. It completes in seconds. The next time you sign into your Google account, everything is synchronized and restored automatically in minutes. Adjusting some remaining preferences is a matter of a handful more minutes.
Powerwash is awesome. See below why and how to do it.