It makes sense Ginjo didn't want Jackpot Knuckle to get upgraded. That fullbring was already risky because of its reliance on luck. If powered up, it could steal the luck from others to empower itself.
All of the match ups fit in some way
Ichigo vs Ginjo (substitute soul reapers)
Kenpachi vs Giriko (eyepatch wearers who have simple powers)
Renji vs Jackie (both had traumatic childhoods)
Toshiro vs Yukio (children who were forced to grow up quickly)
Rukia vs Riruka (both love cute things and felt isolated because of their powers)
Tsukishima vs Byakuya (both are collected swordsmen who hide they admire the ones who trained them)
Ikkaku vs Shishogawara (both are fighter who rely on luck)