Over at Intuit, Barry Eitel has a piece defending the ongoing efficiency of the business card. While perhaps a straw man’s argument, Eitel’s four points still stand.  He tells you why right off the bat:

While networking at conferences is expected, potential leads can appear
anywhere — the bar stool next to you, across the aisle on a flight, or
standing next in line for a sandwich. A business card doesn’t merely
provide information; it leaves an impression.