> I think that standing up is actually really important!
Alas, it seems many people don't - I think I've only been at one place in the last 10 years who actually cared about keeping standups short and focused. I've been at places where standup was 20 people and took an hour every day.
Mind you, I've been at places where standup was only 5 people and still took 30+ minutes every day...
Yes, this is a known trick and that's why it's used in scrum. Like you say it also helps keep things focused as people pretty much cannot do anything but listen.
A famous example of that trick is the UK's Privy Council: "Customarily the sovereign remains standing at meetings of the Privy Council, so that no other members may sit down, thereby keeping meetings short." [1]
We use it to keep things short and focused, since everyone wants to get back to their work and can not do stuff while also taking part in the daily.