Q: Why Sound on Rotate?
A: It seems incredibly easy to accidentally and silently rotate an entity via clumsy keyboard syndrome (R key is next to the commonly used E, T, D and F keys on English keyboard layouts) The unobtrusive and familiar sound alerts the player that something has happened.

Q: Why play sound at location and not just for player?
A: Construction sounds from other players are (generally) played environmentally in multiplayer games. This follows that convention. Caveat - Deconstruction sounds do not seem to be included in that convention.

Q: Do I still need this in Factorio 1.0.0?
A: No, Wube have added entity action feedback sounds including rotation. You may continue to use this mod if you prefer, but I will defer to the vanilla sounds and not continue ongoing support for new game versions.