Selection of Red vs Blue laser technology comes down to a question of the surface material being measured. Red Laser technology is used on solid surfaces, such as painted or unpainted, non-shiny surfaces. Blue laser technology works accurately on all kinds of surfaces including painted, unpainted, translucent, transparent, some plastic, composite, and shiny.
The photos below show the difference between the blue laser (left) and the red laser capability on a red translucent lens: