Since "Gimmick Puppet" is mainly comprised of DARK Machine monsters, this renders them vulnerable to common counters that other DARK, Graveyard-dependent Decks have (namely "Shadow-Imprisoning Mirror", "Bystial" monsters, "Abyss Dweller", "Necrovalley", "Macro Cosmos", "Dimension Shifter" etc.)
Overconfident only does 10 damage for 1 D Energy, but if Sableye has more remaining HP than the opponents active Pokmon, it will do 40 damage, or 50 with a Special D Energy
With so much hype surrounding Gardevoir and Sylveon's presence as one of the most valuable Eeveelutions, these Pokemon boast immense popularity that boosts their value
Once the absolutely vital actions are taken care of, you can get on with the business of building your own board state, chipping away at clue totals, taking care of monsters etc
On the other hand, players prioritise playability to determine a card's usefulness in a deck
For one less mana, were gaining a ton and all that were missing out on is vigilance