I honestly believe that the people who complain about these aren’t using them properly or work for people who don’t know how to use them properly. People have been using some version of the huddle, standup, or SCRUM meeting for a very long time. Whether it’s useful or wasteful is probably more a question about the people who are using them.
I’m afraid that you lose far more than that just going to and from the bathroom, the coffee machine, or down the hall to your office from whichever door you had to walk into. This is not to say that your calculations are wrong, it’s more a question of whether that is a useful metric.