That's really cool!
And like Adam said, adjusting water is not difficult if you start with 0 RO/DI water and know what your targets are. tons of calculators on line can help you know how much of x, y, and z add. The challenge comes in when one additive changes multiple variables, like magnesium sulfate for example. Becomes a balancing act to hit exactly what you're looking for.
That said, you could absolutely create a water profile for cooking and such. Never considered it but would be an interesting experiment.
The best beer I've made to date was a clone of Firestone Walkers Union Jack. I had made it once before and it was ok. The second time, I used RO/DI and adjusted the water to the Burton On Trent profile and the beer was awesome. Made it a third time, not adjusting the water and it was not as good. So in brewing, it does have an impact.