Depending on how Gotham adapts that classic Batman comics storyline, the Batmobile may be incredibly helpful overall.
If that help comes in the form of a boy billionaire and his fancy car, who is Jim to complain?
Bruce isn’t wearing his cape and cowl to drive the Batmobile at this point and he’s clearly taking passengers, but racing around the city in a very nonstandard vehicle to (presumably) fight crime is still another major step toward Bruce becoming Batman.
The birth of the Joker almost certainly means that more murder and mayhem is on the way for the folks of Gotham, and the good guys will need all the help they can get.