Vlad This is a lot like how Firefox containers work. I think theirs might be based on regex though. The benefit of using regex instead of just subdomains is in cases where an app will use a generic subdomain but put the "profile" of the saas app in the domain i.e. https://app.saas.company/company1 or even as a query string https://app.saas.company?profile=company1
I'd also like to push to have this be thought about with the upcoming sessions (i believe that is what they are being called) Allowing closer comparison of running Firefox Containers inside a Profile.