Ultimately, Wizards R&D came to regard phasing as a historic failure
Umbra armor has no effect if the enchanted creature is put into a graveyard for any other reason, such as if it's sacrificed, if the "legend rule" applies to it, or if its toughness is 0 or less
If the copied creature was copying something else, then the tokens enter the battlefield as whatever that creature copied, with the listed exceptions
However, value isnt everything in MTG
Meanwhile, Archmage of Runes not only draws cards the same way, but it also makes your spells cheaper, turning every cantrip into a little engine
Morbid Opportunist stands out as one of the few that trigger when tokens die, so its useful in the right context