Having too many meetings has nothing to do with technology.
As parent said, it's more efficient to send all the participants the same email who then only have to click 1 button - and if they do want to say anything besides accept/decline, they still can!
That way you get a nice list where you can see all the answers, versus 20 mails where you have to read first if it's a yes or a no.
And: It's not a requirement that you actually respond, in that respect there is no difference to regular email of course.
I'm not sure why I'm writing this, it's so obvious, I think you're trolling.