I disagree with you, Paul, but that's fine – we're not obliged to share identical opinions.
My contention is that any e-reader software worth its salt in 2016
must synchronize highlights and annotations – it's a non-negotiable feature, even if many users (or even their majority) like yourself never use highlights and annotations.
The progress in any area of human endeavor has always depended on the
minority that demands
more than just the run-of-the-mill standard.
Otherwise, one might as well stick with atrocious, bare-bones e-reader software from Apple, Amazon and their ilk.