I've played the game for a year and I really can only recognize a small handful of kingdom art and definitely not from the cards because it's so darn small.
Definitely wish the icon was bigger then it would be easy to know which troop comes from which kingdom without having to go down the list and check all of the troops sorting by kingdom.
I can't remember why I was doing that in the past... but I remember doing it very often. Maybe trying to find out what the weekly kingdom event was... I'm not sure.
That's probably it since now I have all the cards besides base mythics I do the same thing each week. Buy whatever packs there are, ascend and level and trait at the same time by sorting upgradable... and then forget about it. In the past I was looking for cards in event chests every week.