Two reasons why guys aren't touching the bar on their chest in the bench:
1. (as Crash already mentioned) they think they can lift more. Same reason they quarter-squat.
2. They don't know how to use their chest on the bench. Simple tip: bring your chest up to meet the bar will stretch the pecs muscles and work them harder. Passively flatten the chest (and upper body) on the bench with the bar half a foot away will not work the chest much and instead destroy your shoulders.
Huge difference between that and deliberately not doing full ROM through a variation like a pin press, floor press, board press or Spoto press.
1. (as Crash already mentioned) they think they can lift more. Same reason they quarter-squat.
2. They don't know how to use their chest on the bench. Simple tip: bring your chest up to meet the bar will stretch the pecs muscles and work them harder. Passively flatten the chest (and upper body) on the bench with the bar half a foot away will not work the chest much and instead destroy your shoulders.
Huge difference between that and deliberately not doing full ROM through a variation like a pin press, floor press, board press or Spoto press.