What Is the Significance of the Strike Price Being Equal to the Underlying Price for Delta?

When the strike price equals the underlying price, the option is perfectly At-the-Money (ATM), and its Delta is closest to 0.5 (or -0.5). This point signifies maximum uncertainty regarding the option's eventual moneyness, leading to the highest time value and Gamma.

The 0.5 Delta means the option has a 50% chance of expiring ITM, and its price is most sensitive to the passage of time.