few different reasons.
neo drivers utalize a neodymium magnet material. much stronger then ferrite magnets and much less is needed. can save weight for same performance as a giant ferrite motor.
neo also has its downfalls with heat ect. heat will effect the charge of the neodymium and it can cause a loss in magnetic force within the magnet itself but this is mainly in extreme conditions. very extreme.
another downfall is cost which is much higher. but in a situation where weight needs to be saved and still put out big performance neo fits the bill perfectly.