That's actually because Mattel is stupid.
Mattel always does that with their Batman toys. It doesn't matter if it's TAS figs, movie figs, comic figs... they always have to make "Neon Camouflage Stomach Pump Attack Batman with Scuba-Mask and Parachute."
The reason is that they believe the only toys that will sell are Batman figs. So they make a bunch of variants of him just to try and sell as many figs as they can.
What, you want him to actually FIGHT somebody? Okay, here's "Ridiculously Large Hands Scarecrow," and, just for fun, he'll look NOTHING like the guy in the movie. Have fun, kids.
That's why Batman toys suck, Mattel has NO CLUE how to do it. It's also why there were so many costume changes in Batman Forever and Batman & Robin. They figured if Mattel was going to make a million different versions of the same three characters, the filmmakers might as well control how they would look.
And even then -- most notably for Batman & Robin - the toys STILL bore no resemblance to anything in the movie.