Yeah, this is one of many extremely old vanillas that are only printed once and never gets reprinted, so most people are unaware about them.
There are even old vanillas who are only printed in OCG and still not in TCG yet.
Even more hilarious, it has higher DEF than ATK despite its offensive prowess being the main thing on its vanilla text.
And 800 ATK isn't even considered high anymore by the time this card is printed in OCG.
Actually you need to follow the condition of the trap card. When you set this card, then the trap card won't working for this turn so you need to wait for the next turn to activate this card, and for the next turn this card should activate, this turn, if you summon spellcaster monster, that new monster cannot trigger this card. It need to wait the next turn to trigger this card.
From all the players I've dueled in ygo omega and for my own experience with the deck there: harpie dancer nor this card are used
I tried this combo for a bit and is too slow, I couldn't get this field spell fast enough in my hand. Channeler is faster and better, it is easier to have a harpie card in hand to discard than somehow getting this field spell
I think there are extra texts that can't be read yet if my hunch is right. It would be like dice roll usual effect based on roll result
(ex : 2 or 3 increase one of your face up monster attack by 500 until the end of this turn)
I think OP is referring to the effect that activates during damage step (copy the attacker's ATK).
This effect does not start a chain, thus it cant be be responded by PS Bounzer.