my question again is why? what about alk? CaOH offers a balanced solution that's easy to use and costs very little.

correct me if i am wrong
deluted CaCo3 in acidic acid comes back as CaCo3 in the reef
the price and grade of the CaCo3 USP grade is better than kalkwasser with its metal sediments

I have no idea. Maybe you're wrong, maybe you're right. But locally I buy kalk for about $5 per large bag. This bag lasts me around 6-8 months. So let's call it $10/year. I then mix it with water, and I know water is safe for my tank in the amount I need to dissolve the kalk in. Now I can't say the sae for vinegar. I use vinegar with kalk, around 80ml. This seems safe. It's a documented process, condoned by chemists.
Did I mention $10/yr?
At the very least, I would run it by Randy over at RC. He can tell you if you're right or wrong, and offer solutions to your questions. Just seems like a lot of work to do something that isn't a lot of work. Know what I mean?