As for why, well, there are a lot of reasons: lots of chase cards in this set, alt art galore, and lots of high-value singles
These ultra-rare pulls appear roughly once every 100 packs, making them difficult targets for collectors
Players can't take actions between the time the creature is randomly chosen and the time at which the rest of the effects occur
And just like every other D&D sourcebook, Mythic Odysseys of Theros goes over how to create an adventure in the setting, the treasures you can find, and the creatures and NPCs youll encounter
In the base set: 1st ED: has first edition stamp on the left | no shadow around the border of the photo | no set symbol Shadowless: does not have 1st ED stamp | no shadow around the border of the photo | no set symbol Unlimited: does not have 1st ED stamp | has a shadow around the border of the photo | no set symbol Is this only for the English Base Set
Aside from that, keep it simple: count the spells, then take into consideration how likely either player is to mill instants or sorceries