The main pro I would say is the very low distortion with their air-damped diaphragm.
Never seen an electrostatic measure well in terms of distortion, if we use the same term used in electronics. ESL's' often _measure_ poorly but sound very good.
The strengths of electrostats usually include superb inner detail and articulation, low coloration, very good to superb imaging, and excellent pitch definition in the bass region. They tend to sound startlingly natural.
Very true. Those large diaphrams can really work acoustic magic. By avoiding floor, ceiling and side to side bounce they can produce some of the same detail as headphones.
Similarly, very wide panel speakers like the Sonus Faber Amati Homage can do much the same.