Goodwills are general worse in my opinion.

They set up an auction site and now all the good stuff is up for auction instead of sitting on shelves

It’s hard to tell without a circuitry layout, but my best guess is that there’s probably capacitors in the power brick acting as an electrical filtration for the motors to make them operate smoothly and reliably.

The capacitors are probably discharging some electricity that are keeping some circuit protective device alive. Unplugging the power brick is probably the only true way to completely remove electricity from the unit.