Looking at different frames for a new build and the Flywoo Mr. Croc got my attention due to the vast amount of real estate for mounting electronics.  I’ve noticed it apparently only has three mounting holes for each motor.  I’ve not seen this before and although it probably doesn’t matter if a motor has 3 or 4 screws I’m just wondering what the reasoning behind it is. Weight reduction? Aesthetics’s? Honestly even two screws holding the motors would probably be secure enough. 

Really for weight reduction. The frame arm is pretty narrow, probably the other reason they didn't want to add the 4th hole.