.....what people forget the magic V2 fluid you'd add to your bad battery? supposed to return an old worn-out 12v battery to new

yep Whitney had quite a few
snake oil products but also had useful things like rings and bearings, way back when I used such things.
They also sold quite a few gidget/gadget things, heck I've probably got some NIB in the basement. Most were cheap Chinese made junk that broke shortly after using, I still remember an adjustable type wrench, I was actually able to bend it by hand like a piece of rubber, total junk not even worth the cost to ship it back for a refund.