Dark or light background, it is a choice, and both can lead to overcrowded, ugly slides full of bullet points. For some reason, people do a better job when working on a dark slide background. Possible reasons?
The dark slide is a clear break from the colour format of most project working documents., there is less temptation to just copy/paste that spreadsheet and call it a slide?
The minimalist dark Apple product launch presentation is just etched in our brain and serves as an example?
Dense bullet points are actually harder to read on a dark background than a light one?
Who knows, but if it works, it works…