The team derives no benefit because the player isn't playing. Why should anything be left in the Cap? What benefit does the team get out of it? Sure there is a player off their Cap but, at the risk of repeating myself, the team isn't getting the benefit of him playing either. So it's a wash, no one benefits extraordinarily.
Initially I thought this but here’s a scenario for you…
Player A is negotiating a contract extension with club. Club wants to give him 3 yrs @ $500k ($1.5m total) but don’t have the cap space, so tell him they’ll do 5 yrs @ $300k, thus he gets the same total amount. The catch is that he’ll announce a surprise retirement after 3 yrs. He doesn’t mind as he’s 30 when he signs. The club has only paid him $900k to this point, thus saving $600k on the cap, with that money still going to the player for working at the club cleaning the dunnies, or whatever. Importantly though, it doesn’t affect the club’s salary cap.
It would be a good way to circumvent the cap, IF they just wiped that amount off as soon as a player retired. The scenario I posed isn’t that outlandish, but it would also take a lot of forethought and planning.
Edit: Or you make it even easier and gift players property rental, cars etc. like the rorters probably do.
Thinking about JJ’s case more, it wouldn’t be that difficult to propose this to a player in their 30s. You could just say we’ll sign you for 4 yrs on $x but if you want to retire after 2 or 3 we’ll give you a cushy job at the same rate. That way there’s no drama with when retirement is decided.