A bytch that's a highly trained martial artist and cat burglar committing crimes as an antagonist/romantic interest vs a boy that the protagonist randomly decides to adopt and raise as his own son, yet he puts him in highly dangerous situations and actually doesn't really care that much because he adopts three other boys and makes them do the same shyt. Robin was created to sell toys to kids bro, solo Batman >>>
Going to be really geeky here lol but robin was mostly created to give Batman someone to talk to. Bill Finger was getting bored and needed someone for Batman to bounce off, and add some levity.
And of course, to get more kids to buy the comics lol.
Also, to your other point, Catwoman is one of the most popular comic book characters in history
for anyone to say "nobody cares about her" means they're smoking the best weed known to man.