Most of my cards work, already (and they show up in the tooltips as "Cards" for the effect). Just not the one I mentioned. Now, if cards are ONLY supposed to work when activated during a prestige (which basically means you're going to wait WEEKS before you can use a single one since you can only prestige duplicates) then their values are WAY too low. Pointless to get something like 1.25x capacity for a single prestige with that huge of a delay between getting to use them.