Chopin is associated with waltzes and mazurkas, both of which are dance forms in triple meter.

A mazurka will emphasize either its measures’ second beats or third beats. This might be kind of difficult to identify in Lang Lang’s interpretation, but a waltz differs from a mazurka by having a more steady tempo and by placing the emphasis on the first beat of each measure, usually matching what you were probably expecting.

I’m not sure how many of Chopin’s dance-form pieces were meant for actual dancing, but it is fairly common for composers to write according to stylistic elements of a dance form without intending the work for an actual dance.