The MACD is important because it provides valuable insights into market momentum, trend strength, and potential buy and sell opportunities. When the MACD line crosses above the signal line, it is considered a bullish signal, indicating that the asset is gaining upward momentum. Conversely, when the MACD line crosses below the signal line, it is considered a bearish signal, suggesting a potential downtrend. The MACD histogram, which shows the difference between the MACD line and the signal line, can also provide insights into the strength of a trend and potential reversals.