Next time you have a standup, look at the clock once you get up to the standup, or that you stop working normally and start looking around to see when people are leaving to the meeting. And then look at the clock when you are back at your seat working again.
People start getting ready to the standup 5 to 10 minutes before, chatting while waiting, etc. Count the time that you have stopped working normally, where you can't do any large task because you know there is a meeting in 10 minutes.
Don't just count the time literally from the moment a person starts giving their status to when the last person finishes, as the real overhead of the meeting is not that.
I guarantee you if you do that systematically and count the complete overhead and not just the literal overhead, that at best it will be typically 15 minutes and for longer sessions half an hour.
They are useful for knowledge spreading and understanding what everyone is working on - we switch projects quite regularly so it’s quite nice to have a birds eye view of where each project is.