I got the TSA card. It's for picking up and screening the shipment and then take it to the air freight at the airport. This type of shipment called for TSA certified. My carrier always call me for this type of load.
For picking up at the airport, DL is good enough. I do quite a few of air freight loads, so TSA card is required.
I heard TWIC is most legit and widely accepted, like the VISA card. TSA is like the American Express card. Lol.....