Having been at a few conventions where people were sharing cards/exchanging info, I'd suggest doing both physical and virtual cards. Virtual cards are usually either a QR code and/or an RFID readable tag that route someone to your contact info, and are nice because it ensures that people don't lose your card before they can enter your contact info.
Best of both worlds approach would be to have the virtual available for people to scan, and the QR code for the virtual printed on your physical card as well.
For a virtual card, I use the ones from Dot Cards - https://dotcards.net/ for both my consulting and my Non-Profit. Seem to work well so far, even with just the free service.
Sq2 - Med Beech, Rosewood finish - 10/12/14/16/18/22 + 6.5x14
Performer - Wine Red, 12/13/16/22 + 6.5x14 (D456)
Phonic - Oak, 13/14/16/22