This technique would be useful only for people who excessively use Ctrl+F while working with the CSS file. :)

Usually websites have consistent design, i.e. repeating styles for active, for example. Styles repetition comes handy in such cases, so I wouldn't drop it, so that I stuff the HTML with new classes and spend half of the day copying the same styles. Also, repetition makes the code longer, thus less maintainable.

Sharing experience and practice is great, this is how we make progress, however, CSS specificity is not that scary or hard to grasp and this is the only argument I find reasonable for using Maintanable CSS on the website.