All of these are actually the same; they just have custom text prompts which try to give you some guidance. For instance, the Hero's Journey template has five slides; the first is Setup, with the prompt "Tell us about the hero and their world before the quest begins." In this respect, Spark Video is the least smart of the apps.
You can create videos using three types of elements: photos, text or (in my opinion) select from a set of rather cheesy iconic graphics. Oddly enough, you can't add videos in Video.
You can change the text-box shape; text and accent colors; typeface; increase or decrease line spacing; alignment; and the transparency of the shape. The style suggestions control cycles through all the variations built into the themes.
Spark is targeted at small businesses, nonprofits and other working folks who don't create graphics professionally, so I guess Adobe thinks that spamming people with a post watermarked #AdobeSpark looks professional.
