Tried containers when it was released but found it very inconvenient to manage. If I understand this solution doesn't even let you have two profiles open at once? That's even less useful imho.
edit: I use Simple Tab Groups which is far more featureful - "Send tab to [group/container/etc]" for example is table stakes.
Of course you can have them open at once, that's what's useful. I have four! And I can open subsequent windows in the right profile, no problem. But it required non-trivial scripting.
I have 3 different profiles, one for each of my current customers and one personal.
Within the customer profiles, I have containers for things like different AWS accounts (although AWS now has that as part of the console), I can have logins to test systems and production systems etc.
The automation of containers is good too, tied to URLs.
edit: I use Simple Tab Groups which is far more featureful - "Send tab to [group/container/etc]" for example is table stakes.