That is (aside from sponsors, who want their logo there) a reason why it looks as it looks and having it somewhat different from event to event.

A shared programmable batch would require scanning them while entering each room, which creates bottlenecks at doors and more effort as each door needs staff and tech (and as soon as you have staff and tech at each door you can also provide all information there, thus the gain of being able to share information into the badge is gone) and you get to privacy issues.

And then half the badges people bring are broken and most participanta didn't ever have one/lost it/forgot it.

This is the only thing that matters buisiness-wise, its what I'd expect people who frequent HN do routinely, pitch. It doesn't have to be logical, fun, environmentally friendly, it just has to make it to their level of control. I've seen very illogical things become "standard" with little or no questioning for why it is now this way for no other reason than someone was very good at expressing "this is the way it is and should be" (i.e. they where very good at BS).