Four-on-the-floor is the simplest possible kick pattern: bass drum on every beat, no syncopation, no variation. It is also one of the most useful. Disco invented the modern version, dance-pop never let it go, and country two-step has always lived there. Most modern dance music — house, techno, EDM, the back half of a Top 40 chart — is some flavor of four-on-the-floor.
The technical challenge is endurance. A quarter-note kick at ♩=120 means 120 strokes per minute, every minute, for the length of a song. Heel-up technique is essential; heel-down will fatigue inside thirty seconds. Bury the beater for tight, modern dance-pop articulation; let it rebound for older disco where the kick should ring slightly.
The third exercise adds the hi-hat foot on the offbeat 8ths — the "open chick" pulse you hear in disco recordings, where the right foot pumps quarter notes on the kick and the left foot pumps quarters on the hi-hat pedal, offset by an 8th note. That pattern, two feet alternating, is one of the foundational dance-music textures.