To reduce bank space, could this item be treated like shards, keys, etc. where you can pick them up in mass and they bypass inventory.
To use them it could pull them up from ( “x place in the inventory”) like keys for entering dungeons when you enter boss fight. if you would like to use one.
As for the penalty of removing one idol to wear the needle, I don’t have anything off the top of my head to offset that change.