Also, of note, this is the first movie/TV-based show in a while to use actual footage from the source material rather than recreating it with animations or re-enacting it with the cast.
It depends on whether they can get the rights from the film owners, I guess. Given that Adam, Grant, and Tory used to work for ILM, and given that the producers were presumably willing to shell out more money for this special, I'm not surprised they got the rights.
On some of the episodes on Netflix, the clip rights have apparently lapsed, since the clips are edited out. For instance, the "Black Powder Shark" myth based on the movie Deep Blue Sea
no longer has the movie clips included in the streaming episode, which is a bit confusing if you're seeing it for the first time, since it means they jump right into the preparation without explaining what it is exactly that they're testing. It's too bad the producers didn't plan for the contingency of losing the clip rights and make alternate animation segments to accompany the same narration.
Although they went well beyond licensing a few clips here. They would've had to pay for the right to use trademarked logos, costume and creature designs, and characters like R2 and Chewie, plus they licensed the John Williams theme for the opening.