Chrome profiles are a great way to separate work from personal accounts and avoid having to constantly sign in and out of web applications.
Many services out there only allow you to manage a single account at a time. This is generally standard behavior for web applications.
When working on web projects, you likely have an account with a Git host, deployment platform, and content provider, perhaps among many more. Separating between work and personal accounts, or being able to act on behalf of a freelance client often means logging in and out of these services.
That gets old real fast.
Chrome profiles are a great solution for curbing this annoyance. They allow you to create silos of browser history, extensions, and sessions. It's a fantastic way to keep accounts separate without having to constantly sign in and out.
I tend to have two or three profiles active at any given time, and it's been a massive boost in productivity for me.