Stationary lights create shading under the canopy due to the light being absorbed by the top leaves
This causes a colour spectrum shift under the canopy producing leggy growth profiles
Uneven distribution of light energy causes plants to bend towards the highest point of light instensity, resulting in poor growth in the remaining areas
Essentially some of your plants risk ending up being to far from their light source, and some will inevitably end up to close and burning the top foliage
1000W are particularly fierce in this respect and benefit particularly well from being mounted on a Jupiter 2 light mover