For the things that are happening right now.
Your X account as a code. Delays, changes, doors opening late, the thing that went wrong and what you are doing about it — printed where people are waiting for exactly that.
More style options
Light grounds only — the code has to stay darker than what it sits on.
Where these earn their keep
Venues, stations and queues
Where the useful information is the last hour's, not the printed sign's. A code on the barrier beats an announcement nobody heard.
Conferences and panels
On the slide, on the badge, on the stand. Speakers get followed in the minute after they finish talking or not at all.
Support and status
The account people are already checking to find out whether it is broken for everyone or just them.
Questions people ask
Does it go to x.com or twitter.com?
x.com, which is where twitter.com sends everyone anyway. Paste either and it works.
Can I point at one post?
Yes. Paste the link to the post and the code carries it exactly, which is the version to print on something about a specific thing.
Do people need an account to see it?
To read a profile, usually not. To follow or reply, yes. That is X's rule and it changes from time to time without asking us.