Use 'none but' to stress an exclusive group that can do something or is affected by something.

Exclusivity Emphasis

Can be used for dramatic flair to highlight courage, skill, or another virtue.

Dramatic Effect

'None but' can be hyperbolic, not always meaning absolutely no one else but the mentioned group.

Suggests that something is appropriate only for a particular person or group.

Highlights the need for expertise or a high level of skill.

Implies that no one other than the specified group should attempt or be involved.