Is the F value of mobile phone aperture good or small?

There is no good or bad aperture size.

For photography, the F value of the aperture of a mobile phone is not absolutely "good" or "bad", but depends on the desired shooting effect and the specific shooting scene.

Small aperture and large depth of field can keep the foreground and background relatively clear. This is useful when shooting landscapes, buildings or scenes that need to show more details.

A large aperture can produce a smaller depth of field, blur the background and highlight the subject. This effect is often used to shoot portraits, close-ups or scenes that need to emphasize the subject, creating a sense of art and layering.