pH balanced nutes are convenient. I haven't tested my reservoir in years, because it never changes in any meaingful way.
The plant selectively takes in various nutrients which will cause the pH to shift over time no matter what (without runoff). A pH balanced product may take longer to drift but without runoff it will happen. Religously getting 10% runoff with soilless growing method will 'reset' the rootzone each time and mitigate such potential for future problems. This is what causes faster than soil growth -- 100% plant available nutes maintained at healthy levels around the roots that won't impede each other. Not getting runoff essentially throws that benefit out the window.
The dynamics of an autopot eliminates the primary benefits of soilless growing method. It's a contradiction to use a soilless medium in a bottom-feed setup. Like pissing into the wind, it does the job but maybe not the best combination.