Resolution is one of the most important aspects of any camera image. In slow motion it could be the difference in showing important details or just obscure an event all-together. In machinery failures during manufacturing; low resolution and high resolution can mean the difference in spotting a crack or bend in the process and that is hugely important.
For film makers and videographers resolution weights a lot when deciding upon a slow motion camera solution. Not to long ago slow motion cameras at or under 1 megapixel 1024*1024 for example was a novelty and a luxury. Nowadays 1280*720px or the lower end of HD resolution is easy to find and widely used. However 1080p and or 4k are the resolutions that seem to cause the most interest.