They did big box-o-junk releases for the Batman animated series and then normal editions later on. This is just a transparent attempt to fleece the impatient.
Except the people who make other classic cartoon releases happen have told us that they had little to do with this set, and that there's no plans for anything else even if this does sell.
Apparently, WB had to be talked into making the set what is it. What they really wanted to do was just make a Blu-Ray version of this DVD, because they thought the Funko was the thing that was going to entice collectors.
Between this, the Platinum and Golden Collections and HBO Max, almost...