As a developer I want to move parts around that don’t interact with anything physically, and roblox makes my game slower when I do this because it updates a ton of unnecessary physics data every time any part moves. These parts are used for effects, effect emitters, adornments to other parts, map detail, etc.
Most of the parts I create from lua are not intended to interact physically in any way.
So I suggest a new part type that doesn’t have any physics interactions. No collisions, no gravity, no Touched event, nothing.