Been using this in our Workplace account. Most people don't like it because they are luddites, but I absolutely love the summaries for those multi-week 50 email threads. Also the ability to quickly insert an absurdly overly formal response to a simple request as a joke is amusing.
I do wish it had the ability to respond to emails for me though with a prompt.
Oh please, not everyone who disagrees with you is a luddite. If this feature is so great they should make it opt-in. People were clamoring to get early access to Gmail; if these summaries are as good as you assert then people will happily enable them.
The fact that Google doesn't even provide an option to disable this one feature is telling. That strongly implies that Google managers agree with most of this thread and think this is more about juicing AI metrics than providing real value to users.