According to Aaron Forsythe, current VP of Wizards , the design of Skullclamp was changed at the last minute from giving the equipped creature +1/+1 to giving it +1/-1
Jaden, on the other hand, primarily relies on Fusion Monsters as his main strategy, with an occasional big Main Deck monster
to merge the original 3 "Cyber Darkness" monsters to create Cyber Darkness Dragon, or use Overload Fusion to merge 5 "Cyber Eclipse" effect monsters to create Cyber Darkness Dragon instead
While one gem mint 10 card recently sold for a whopping $15,000 on eBay, you're more likely to find them for sale for about $1,000 in the best condition
The sealed format also makes it attractive for long-term collectors who prefer keeping rare One Piece Card Game items unopened