That's disruptive!
> Standups are in my experience much more effective at signalling blocking issues than slack.
If you are using Slack, you have already lost the battle for productivity.
> If a couple of minutes per day kills your velocity, as the article claims, I wonder what else you're doing during the rest of the day.
Literally any interruption destroys your focus. A pending appointment destroys your focus. If you use Slack or E-Mail notifications, people never even attain focus, so in that sense it's not a loss.
> And even then I'd guess it's useful to have a quick refresher about what you're working on.
To a first approximation, nobody cares what you're working on. Nobody should care what you're working on. If your developers need to constantly communicate with each other, something is likely very wrong with the way you split up your work.
Daily standups pre-suppose that there's always stuff to communicate and that everyone is always involved, but only once a day and only briefly. This is complete nonsense. You need to be able to adapt to the situation. You need a meeting? Have a meeting with whoever is concerned. Have a follow-up meeting. Take your time and focus on the issue, then nobody will even feel like time is being wasted.
