How does 'Pyro Clock of Destiny' work in YuGiOh?

Answer 1

Pyro Clock of Destiny advances the turn count by one. Normally, this would have no effect on gameplay because of its secondary effect that states that the current turn continues as normal. However, Pyro Clock of Destiny affects cards such as Swords of Revealing Light and Final Countdown. If these cards are active, Pyro Clock of Destiny simply advances their turn count. Swords of Revealing Light will stay on the field one less turn for example and Final Countdown will declare an Automatic Victory one turn faster.

Answer 2

Some cards count the number of turns that pass, and what "Pyro Clock of Destiny" does is increase those counts by one. "Final Countdown" counts 20 turns after it is activated - "Pyro Clock" will add one to this count, so only 19 actual turns needs to pass.

However some cards countdown during Standby Phases, "Pyro Clock" will do nothing to these, it does not literally make a turn pass, just add one to the count of cards which count turns.