Final releases (including beta) should strictly show features that are finalized to prevent loss of data, old API clanging around, and the overall quality of the product (Blender) presented. Note that rendering should never be affected by user preferences, so this is only changing things in the UI level. Development note: This is reset experimental UI on file load. Also note: to hide RNA (needed for hair and particles) will be done as a separate patch. Differential Revision: https://developer.blender.org/D8606