Assuming we make it through without a lockdown, and if there is a Good spread of results, then it was probably a good way to get through a stack of games.
The NBL Cup games are in addition to the originally-scheduled 28 regular-season games. It achieves nothing
in terms of "getting through a stack of games", it just makes things take longer while blocking out an entire month of the season where they can't allocate home games to clubs that might need them given lockdown situations.
None of the stated reasons make sense. The only thing I can think of is that given the Boomers were originally meant to play in the Philippines, they a) would have had to send NBL players and b) would have been away for a month or so given quarantine requirements at each end. Thus, the NBL Cup could be played in that month to keep the other players busy and keep the NBL in the spotlight. Remember, there were originally discussions as to whether the NBL Cup games would count towards the season or not.
Once we were scheduled to play NZ instead, an agreement could be made regarding the types of players who would compete, the NBL guys were free to stay in, but the Cup had already been announced and promoted, without ever acknowledging its true purpose, and thus couldn't be walked back from.