There are partner-dance styles that emphasize connection, sensuality, intimacy, subtlety, etc. They are "hug-and-move" styles, including Argentine Tango (close-embrace social styles), Kizomba, and "sensual" bachata.
Yes, they feel good. Dancing with physically close partner can be very sensual experience. They can make most out of crowded dance floor. They command whole set of unique techniques to dance small and nice.
But, as a "show" dance, they fall behind of many other dances. Why?
Because, spectators cannot "see" it from a distance, from 20 feet, 50 feet, or in a large stage, the distance can be 150 feet away. The dancers are tiny figures of size of inches.
It takes different techniques to "show" your dance across the distance.
Let's take salsa dancers, showing solo drill. They try to show "cool" moves, as well as the quality of the motions and nice shapes of their bodies.
In the case, their motion range is limited within what a single body can do. Solo salsa is a "wiggly" dance, and the visually appealing distance is limited within a range that we can see the motion and shape. Many solo salsa dancers use agility and speed to add appeal, but within a limit of what the dancer can do.
Ballet people have hundreds of years of history of "showing" the motion and body across the distance. One solution they reached is the notion of "line". As a habit of human brains, lines are highly recognizable to us. There are "lines" human body can make. Ballet dancers extend body lines to clearly show them. Excess fat and meat obscure the lines, and that is why ballet dancers are skinny. They also use their bodies to "draw" illusionary lines in the air.
Signaling/gesturing moves (wave, salute, shoulder shrug, etc) are actually highly visible and understood, too.
In a partner dance, two people are dancing together. Two people greatly expand options to appeal visually.
For example,
Two bodies physically occupy more space. The bigger, the easier to see.
They can draw lines in the air, using partner's body as an extension of your body, and the lines can be much longer than ones solo dancer can draw.
Partner dance allows gravity-defying illusions with weight supporting moves like lifts and drops.
Partner dance adds viewing angles and complexity.
Appealing postures can be shown with partner's support. Think Arabesque. It is pain to do it by oneself, but balance-supporting partner can make it a lot easier to do it.
With compression-propelling motions (as in swing dance), partner can move faster than he/she can by oneself.
Likewise, many moves that are impossible or very difficult by oneself can be done with partner.
Appeal of partner dancers increases when they both are conscious about how they look as a couple. Also, uneven couples can be spotted in not a good way. Ballroom people use "frame and picture" analogy. It is applicable to pretty much all partner dances. My old instructor used to say that he would take any partner and win competitions. I thought it was bull, and think it is bull even today. There is no immediate cure for uneven dancers. ...I digress.
Working with many dancers/multiple couples is dealing with group and formation. Making group dance looking good is choreographer's job. It is beyond a single or couple dancers' work, and definitely third person is needed to design the group dance effectively.
These points are not relevant if you are a social dancer with no regard to how you and your dance look. But for many other dancers who care about how their dance look and how they convey positive impression to spectators ( in other words, if you are taking a step toward an entertainer-dancer), yes these points are something to think about and to take seriously.
Just leaving a note on something that came up in a party this past weekend.
