For each card type among those, you can put one card of each revealed type into your hand
Threaten effects, or effects that temporarily steal opposing creatures, aren't super popular in Commander, though the equation certainly changes when that threat's attached to a 10/10 and also morphs the 'borrowed' creature into an annihilating monster for the turn
Similar to a reanimation deck, you can use Athreoss ability to ensure an important permanent sticks around and take advantage of ETB effects multiple times
Lets say you have some Magic cards with a certain theme or mechanic you like, and you want to get more cards like them
A fun, flavorful product that eventually became too middle of the road to keep going on as it was
This was more of a luck (or unluck) of the draw type of deal