In my view it's nowhere near as nice as it is on Firefox, with site isolation (Facebook, Google, Twitter, reddit), temporary containers, and a myriad of other add-ons that improve managing them (keyboard shortcuts and transition rules are the two I use the most).
its more like Vivaldi's tab stacks or FF's Tree Tabs. With groups there are no inherent additional security mechanisms in place to prevent cross-group contamination/access. i.e., two different tab groups can access the same site data.
containers however are completely isolated from each other. i.e., two different containers have completely different sets of site data.
Are you saying the biggest advertiser on the planet likely doesn't want to add functionality that could potentially hinder tracking for advertising purposes...?
I am shocked, shocked and appalled. /s