All registered users, transferred from the online system or registered in the field: Doesn't matter. Print their badges in short time.
Hotel vouchers also printable in the same time with badges.
It is possible to prevent clutter with the "self check-in" kiosks where participants can print their own cards in crowded organizations.
Participant tracking can be done with the barcode attached to the card or the paired RFID and can be monitored online. Detailed reporting service can be offered after event.
How long the participant spent time in the hall or which sessions they attended can be monitored.