The red Delete button is often considered better for critical actions like "delete" for the following reasons:

Color Association with Danger:

Red is universally recognized as a warning or danger color. It draws attention to the gravity of the action, such as permanently deleting an item, which may not be reversible.

This can prevent accidental clicks by making users pause and reconsider their decision.

Increased Visibility:

Red contrasts strongly with most user interface backgrounds, making it highly visible and easily distinguishable.

This ensures users notice the button, especially in high-stakes actions like deletion.

Emphasizing Criticality:

Using red communicates the critical nature of the action, making it clear that this button performs a significant, potentially irreversible task.

Consistency with UI Conventions:

Many user interfaces follow the convention of using red for destructive actions like deleting, removing, or canceling major operations. This helps users quickly recognize the intent of the button.

User Cognitive Load:

The red color reduces the cognitive load by quickly signaling to the user the button's function without requiring detailed reading or analysis.

Why the Non-Red Design Is Less Effective:
The second example uses a neutral or less attention-grabbing color, which doesn't highlight the critical nature of the delete action.

Without the color cue, users might treat the action casually or confuse it with other less critical buttons.

Ideal Use Case:
For critical actions like permanent deletions or high-impact operations, the red delete button reinforces the severity and ensures the user acts intentionally.