It was far more important during my single days which coincided with the disco era. Singles meeting in nightclubs was the most popular avenue. Asking a woman to dance also did not require a guy to use any "pick-up lines". The conversations started (after) the dance. In that sense dancing was important because it was the "ice breaker".
However as one gets older they are more likely to turn to online dating to meet someone rather than standing in long lines to get into a nightclub, pay for over-priced drinks, working up a sweat on the dance floor, feeling too old be in the club scene, or having to worry about having too much to drink before going home.
Most couples and especially those who are married tend not to go out dancing very much. If they do it's usually while on vacation, attending a wedding reception, or a private party such as a company Christmas party...etc Dancing is unimportant at this phase of my life.