@Gargron I feel you are overlooking the usefulness of quotes. I have used quotes on Twitter to qualify WHY the content I was retweeting was worth looking at.
Simply just retweeting content may make people overlook the importance of said content. However, if you retweet content and write a qualifying comment such as "This is a very strong observation, because…" etc., that has real value.
I agree with you, the feature can be abused, but would you not agree almost all features can be abused?