In the case of the former, its because the best choices vary not only by color identity, but often by specific deck building limitations: Seismic Assault and many other red effects want you to play an extra-high land count, while a black deck with reanimation and Tortured Existence obviously cares about discarding creatures
It's essentially a second copy of Phantasmal Image, so any MTG commander deck that wants to run that may also want one of these (Gyruda players, looking at you)
Its base power and toughness are 5/5
Amused by Kairi's request for assistance and happy for the chance to wreak havoc, Hidetsugu agreed to fight alongside the dragon
Initially printed in Tempest, Altar of Dementia saw a reprint in the original Modern Horizons set, making it Modern legal
Its one of the more expensive cards in the Fallout precons, and for good reason