I have both cardamom pods and cardamom seeds in my spice rack. I think they taste very similar.
I do think the seeds are more practical, because, in order to get the flavor, you need to split the pods, which is a bit fiddly. I often bite them to split them open, not very hygienic, but sometimes I do it with my nails. With seeds, you just sprinkle what you need.
The main advantage of pods is that you get the flavor and can then fish out the pod at the end, so you don't get the little seeds floating around.