It wasn’t collectively known that software was hard to do right at that time. If it always performed as intended it would have made for a less expensive and perfectly safe machine. It’s the textbook case in doing software wrong because there wasn’t one that happened before it.
Batman and Dracula are characters that share a nocturnal bat related identity and are also wealthy recluses with mansions. So yeah, that’s pretty much the joke. Whoops Harley and the Joker got them confused.