One possible reason (the most popular theory) is that ante meant that playing too many cards in your deck would mean risk of a high value loss
Eggman's most powerful effect occurs during your end step, which only happens once each turn
C Common Wasteland X SPELL Field All Dinosaur, Zombie, and Rock monsters on the field gain 200 ATK/DEF
Its one of those things where if you dont know what it looks like then the pic doesnt mean anything to you
3 Lucario ex Battle Deck Lucario ex is a powerful card, especially with its signature Aura Sphere attack, dealing 160 damage and 50 more to a benched Pokemon
Of note, all extra deck "Artifacts" have a number of circles equivalent to the number of materials needed to Summon them (2, in the case of both "Artifact Durendal" and "Artifact Dagda")