I like the concept and the text of these Trading Cards and the shops that buy/sell them. I keep taking them from each Zirax I kill like its a trophy.
But is there any other special value to them other than their small credit value? Like completing a set unlocks a secret mission or becomes an expensive single set item after doing UNKNOWN mission XYZ???

I didn't see any details online, but I might have overlooked something.

Just curious what others do. Sell them? Throw them away? Put them in a box that keeps growing forever just because...