For anyone coming later, the first half of the video is superfluous to the meme, start at 3:18.
I agree with the video's interpretation of the first ruling, that that would be a reasonable use of a ready action.
I'm assuming that even though the DM pretends to be annoyed, he actually thinks all these shenanigans are awesome and is bending the rules to let them work.
Outside of the immunity to Charm it was still a decent use of an action/ready action.
I think you could rule either way on if the zombies/lich would jump off a cliff after the gem, since the spell mentions that they specifically stare at and approach you (not the gem).
Casting a spell and holding it uses visible components the hobgoblin could react to.
Incite greed also explicitly says that the creature avoids obvious harm while approaching you and does nothing beyond approaching you. If the would always run after the gem (forsaking personal safety to do so), this would be noted in the description.
Casting a spell and holding it uses visible components the hobgoblin could react to.
I'd think it'd take at least an arcana check to know that the spell you're holding is Jump. So yeah, he could react, but would he necessarily be able to react in time to stop you from casting the spell? Not to mention, if he reacts just barely not in time and jumps haphazardly, one could argue the Wizard jumped farther and therefore wins.
I assumed it to be about weird interpretations/effects of spell that are either Raw but stupid (like find traps finding intentional clauses in legal documents) or common sense interpretations that still lead to weird outcomes (using bead of force+levitate+thunderwave to blast the BBEG into orbit). Because why make a video about people misinterpreting spells without making clear that this is unintended?
I think the weird part of Gate Seal was just its duration and casting time(seriously why does it take a minute it's a 4th level spell). And as for Incite Greed - is that misinterpretation not reasonable? The charm is that they stare at the gem greedily but it...makes no mention of what happens to the gem, or what happens if the gem leaves your person.
I takes a minute because it's not meant to be used in combat. I think for the power it has in the situations it applies, its very reasonable that it would be a spell requiring prep time and not one to just be popped of in the middle of combat.