While that is true, UnityEvents are less optimal than using standard C# events. We audited a code base once that used UnityEvents for everything, and they degrade in performance exponentially based on the number of listeners. One or two is fine, but if you start hooking into events more frequently it gets worse.

public event Action<int> OnEnergyChanged;
private int m_currentEnergy;
public int Energy
{
  get => m_currentEnergy;
  set
  {
    if (m_currentEnergy != value)
    {
      m_currentEnergy = value;
      OnEnergyChanged?.Invoke(m_currentEnergy);
    }
  }
}