They look at their own collections and survey what they have stored or squirreled away in drawers, binders, boxes, etc
Putting the double damage on top of that is super-sweet
Even the smallest Cat becomes a force to be reckoned with under Eldrazi Conscription
If we want to keep playing them, we need to pay for them
Now, Im not saying that you have to be that paranoid when youre kicking around your LGS at the end of the night and youve played with the half-dozen people in the room for years, but I will always follow this rule if Im in a new shop or hanging out at a major event
"Once each turn" is a bit of an annoying limit, but in just two turns you'll have enough to pay for Strefan's ability, making it worth the downside