It's not that I NEED more features. I commonly shoot with my trusty old Olympus OM-1 manual film camera that doesn't even have a working meter anymore. (use a $5 external old one I got at a garage sale with it), and it does just fine.
It's more like "This camera has all kinds of sensors and motors on it, and why shouldnt customers be able to get their hands on them for free, since they already exist in the camera?" Well as it turns out, they can. Sort of (API is not exactly as user friendly as it could be. Java for example would be an obvious choice for a language to write the coding API in, for easy communication across various devices, but Canon only has it in C natively, and firmware is not very "plug and play").
Also, most of the things you would use this for would be re-optimizations. For instance, different ergonomics, button layouts, or different autofocus software to meet abnormal needs, or whatever. Such that you would install it (or link it to a removable peripheral) and then forget about it / have it work in the background. That doesn't neccesarrily add up to more buttons to push or any more complicated of a shooting experience.
A good example would be if you are a sports photographer, and your camera's auto-ISO feature assumes that you are shooting handheld still subjects. Thus, it will only crank up the ISO once shutter speed goes below 1/60th or something like that.
But if you're shooting fast moving things, you would want ISO to be bumped up if it falls below 1/500 or 1/1000th perhaps. The Canon 7D can't do that normally, for example, but it probably could with custom programmed firmware. This is not a feature that you would ever think about again, though, probably, after installing it. Thus, it improves your exposures for your usage case, but does not add complexity.