I started to grind some coriander seeds last Saturday, then thought, hang on, why not dry fry them first, which I did and the difference was amazing.
Hang on!
You said that you only started to do this last Saturday (i.e. 3 days ago!)! I've been doing it for over 20 years! :
LOL, just having some fun with you Coryander thats all...

You are quite right, if your going to store these spices for some time then grinding them is probably just what you need. I have to admit that when I cold grinded them, the grinder got pretty hot

But if you're going to use them quite regularly, then small amounts roasted are nice too...
Annnnnnd........ just because we have only been on this web site for a short period of time, doesn't mean we also haven't been cooking for 20 years ourselves....
I don't think Coriander and Cumin was in GB when I first started out........
As my grandpappy used to say.......

lol