Batman is just tacked on for no reason other than to be able to call it a Batman movie.
shareCame here to say exactly this.
I liked this movie, but it's clearly not a Batman movie. The thick 70s influence throughout, homages to Bruce Lee, James Bond, blaxploitation... Batman appears as a character twice throughout the movie and I'm not sure the name Batman is said even once, referred to as simply "that costume" and called Bruce at all times.
My guess is that work was already underway on the movie, a love letter to 70s media, when someone from marketing came down from on high and told them it simply wasn't going to be profitable unless they could tie it to a big franchise name. So they replaced one of the characters with Bruce Wayne, set a chunk of it in Gotham, and turned it into a Batman movie. He wasn't even the main character in his own movie! That would be Richard Dragon, he is clearly the real protagonist.
It's sad but true that these days animations like this simply won't get made unless they can tie it to a recognised brandname or franchise, it's far too risky as a project. In a fairer world this would have just been called "Soul of the Dragon", Bruce Wayne would have been a different character, and it would have been an attempt (failed or otherwise) to start a new franchise based on Richard Dragon. (Hate that name though, doesn't sound right at all).