Actually, the dust is more pronounced on these examples you gave (GoPro, mobile phones) because of a (pretty complicated) relation between the size of the senso

Actually, the dust is more pronounced on these examples you gave (GoPro, mobile phones) because of a (pretty complicated) relation between the size of the sensor, the aperture and the depth of field, not necessarily because of the wide angle, although it exacerbates the problem. Greasy is something else, and affects all lenses pretty much the same way, by messing with the transmittance and refraction.