No what he meant was that after you special summon the banished monster this card stays on the field until that monster is destroyed, but if you tribute that monster the trap stays face up on the field forever if it isn't destroyed somehow.
Can Escape from the dark dimension special summon Gate Guardian when it is banished?
No because even though it is a dark attribute monster it can only be special summoned through it's own effect.
I think the cad is bugged had some fights where it stayed on the field waisting a spot ( not cool since you only have 3 zones )...
brought my winged minion back to tribute it for my summoned skull, happend more then once.
Depends. If Dark Necrofear was banished (either from the field or the grave) after it was Special Summoned by its own effect, then it does work.
this is great in a RED-EYES deck having FUSION GATE to summon BLACK METEOR DRAGON banishing red-eyes (AS Fusion Material) and summon it on the field by this card giving you 3500 and 2400 total of 5900 enough to win even if is a monster of 1900 or less face up 5900 - 1900 = 4000 if the monster is face down is good to use red eyes to destroy it and use black meteor 3500 plus and equip spell of 500 to OTK 3500 + 500 =4000