I am still mainly focused on improving the app, but soon I focus on marketing as soon as I see that a group users really gets hooked on using the product (and that group can be very small). One good way to show what the app can do is short screen capture videos I think. I quickly put two together, without editing, just my playing around.
The first one creates a data table with integrated bar chart (notice how it lines up) from scratch:
The second slide uses the built in slide template bank (the app has access to the same slides as you can search online). Notice how you pull in the template, quickly add in columns, delete rows, and pull in another image. (I am using the beta Unsplash integration here). They key problem with pre-designed PowerPoint templates is having a design layman adjusting a template that was created by a pro. SlideMagic solves that.