Complex sentence: Compared to a knockout tournament, the Swiss system has the advantage of not eliminating anyone: so a player who enters the tournament knows that he can play in all the rounds, regardless of how well he does.
Split into simpler sentences: Compared to a knockout tournament the Swiss system has the inherent advantage of not eliminating anyone. That means that a player can enter such a tournament knowing that he will be able to play in all rounds, regardless of how well he does.