Imagine being able to film unlimited 8K video, or capturing images of deep-sky objects all night with almost zero noise. While there may be better ways to manufacture a camera without heat issues, there is a market for a camera that could be cooled beyond the average current camera housing. Water-cooled cameras are not anything new and for that matter creating a custom water cooling system for a DSLR has been done many times before too. Dedicated cameras in the astrophotography market often come water-cooled in order to reduce the heat that leads to increased noise during long exposures. To that end, several astrophotographers have set out to create their own version with a popular DSLR for astrophotography. As 8K has become more mainstream in smaller form factor cameras so have heat issues. Even when those issues don't cause the camera to shut down completely they do lead to other issues like higher noise and hotter devices.
The projects over at DIY Perks are often experiments in the possibility rather than the best solution for a problem and this new video is no different. It's really interesting to see different cooling mods and the results in recording times that can be achieved. It is unlikely everyone is going to go out and build water-cooling setups for their cameras but the results speak for themselves. So maybe there is a market for a 3rd party company to produce a new camera back with built-in water cooling. Or at the very least the video shows a vast improvement from just improving the heat transfer plate that would be pretty simple for a company to produce and consumers to install.
While I don't think the vast majority of consumers have a need for any changes to most existing cameras on the market there are niche uses like astrophotography that would benefit from cooling modifications and maybe this could lead to a new product market similar to the one built up around PCs.
If Canon wants to send me a new Ra I'd be happy to water-cool it and do some testing to see what kind of improvements can be achieved.