There are just so many advantages to making slides with very simple shapes:
- It focuses on what you want to say only
- They are easy and quick to make
- They look highly professional without a degree in graphics design and/or the full suit of Adobe software
- It easy to create a sense of motion
- There are no issues with images/illustrations that do not fit your color template
An example is this poster by Network Osaka (actually must better than a concept designed by me a year ago):
SlideMagic: a platform for magical presentations. Free student plan available.