These triggered effects will almost always cause an amusing backfire, with the most lethal abilities coming from the games event cards, which reference specific iconic moments from the story
Summon: LeviathanSummon: Leviathan, in particular, is extremely potent in such builds as it delivers a Whelming WaveWhelming Wave for its first chapter and then draws you a card whenever one of those creatures attacks (a trigger for each one, that is)
Shining Charizard cards with the sought-after 1st Edition logo on the left of the card are significantly more valuable than cards without
Blue Suns Twilight Blue Sun's Twilight is a strict upgrade to Entrancing Melody
The ability to gain huge numbers of loyalty counters here is significantly more useful than the -12 ability which, although undoubtedly strong, is costed at an impractically high rate (two points of loyalty higher than on the original card)
There are obvious times you might want to do this (an Inevitable Defeat or Lightning Helix is about to give your opponent life) and less obvious ones