The only activation requirement is that you have an Eldlich Monster on the field
It's the most powerful basic attacker in the game, with a potential 150 points of damage per turn
SE Secret Rare Over Capacity X TRAP When your opponent Special Summons a monster: Banish all face-up Level 2 or lower monsters on the field
I like it more for its Passionate Singing, but Blazing Shout provides a reliable way to take down literally every single Stage 1 or Stage 2 Pokmon (from the set) that isnt a Pokmon ex in one shot, and it will do substantial damage to any Pokmon ex as well
Some booster packs and card tins can sell for thousands or tens of thousands of dollars depending on the set, so do your due diligence and compare several selling options before making a decision
Celestial Guardians will also feature two booster packs spotlighting Legendary Pokmon Solgaleo and Lunala, as well as a themed binder cover and display board to show off Trainers collections