So what makes them more worthwhile than the adapter w/reg + trimmings?
well.....right now, hard to say as they're fully discontinued and pretty much gone. When regular price, these were over 100.
lets compare shall we:
jacpac $19.83+tx= $22.41 + $5(tank fill?) = $27.41 + gas QD($6?) = $34ish out of the gate and on your way. jacpac comes with built in reg, saving your expensive reg from being broken if tipped over, also has a hose too.
adapter $14.99+tx = $17+shipping?lets say $5? = $22 + painball tank? $30? + regulator(probably already have, but lets add it in) $50? plus tank fill $5 + gas QD and hose $10? = over $100