I think Container Tabs are a better fit for the way most people use multiple accounts online.
Plus it enables the Facebook Container extension, which sandboxes all facebook-directed network requests so they can't track you across the web.
And the third party Container Proxy extension lets you set different proxy setting for different containers. So your work tabs can use a different network route.
Container Tabs are not a replacement for profiles though. It doesn't let you have different bookmarks, extensions, theme, etc, which doesn't work when you want to have a separation between work and personal stuff.
Firefox already supports profiles, all it needs it's a simple UI to switch between them. Profiles + Containers (and everything that comes with them) would be perfect.
Plus it enables the Facebook Container extension, which sandboxes all facebook-directed network requests so they can't track you across the web.
And the third party Container Proxy extension lets you set different proxy setting for different containers. So your work tabs can use a different network route.