Are you sure? Mine certainly doesn't. The black cardamon I have has an almost acrid smokiness to it but not my black cumin which is more like a darker more intense cumin taste, but certainly not smoky. 
The insides of black cardamon has more of a medicinal flavour but the outside is smokey
One place I knew interchanged the two spices, with no discernible difference to their rice
For a takeaway portion of rice I wouldn't use more than about ten black cummin seeds
Literally a pinch
It needs to be kept subtle
I can understand anybody not liking black cummin though, it is very strong
and yes, after five years most spices will be past their best
But believe me, these little devils still remain robust
I suppose that's partly due to them not being ground
I had 10 year old whole star anise and that kept fine, too
I keep my whole spices in jars and in the dark
Ground spices go off in a few months
As soon as they are ground, the clock is ticking
Talking of hating things, I once bought some black salt
That stuff has got to be smelt to be believed
It smells almost like rotten eggs
After the recipe was tried, which required it, I threw that away
Seriously never again