I also keep holding the cards. I sell/sold only the Dark Energy Crystals (DEC). Currently I am leasing out most of my Splinterlands cards. This is where the Dark Energy Crystals (DEC) is coming from. And this is why my current max tier is Bronze I. Otherwise it would be Silver III. My total owned Splinterlands card collection is currently worth $168.12 HBD. This is still more than what I currently have in Hive Dollar (HBD) savings ($137.80 HBD).
