The lack of dialogue is an interesting stylistic choice for Battle Stage 3, but also perhaps a practical one. After all, there is a lot of background story to some of the final races that would otherwise detract from the point of the battle stage OVAs - which is to focus on the races themselves. So I think it was a necessary decision to cut the dialogue entirely and approach this stage from a different angle. In a way, it makes you feel more immersed in the race. You get to focus more on the spectacular animation of the cars and the soundtrack as the driversmentally and physically battle it out. It takes some getting used to but in the end, it almost has a hypnotising effect.

Ultimately, this is worth watching if only for the final 2 races, which are considerably extended, and as a result it feels like you're watching them in their entirety, instead of dashing back and forth between the characters and story like in the anime. I thought these races were especially cool and thrilling and actually benefited from the dialogue-less approach. While watching you get a sense that this is what the producers wanted to create all along - a battle with the viewer purely in the spectator seat. It's a pretty glorious send-off to be honest.