Yes
It works but its unnecessary. Kinda makes the phone pointless too IMHO
Why? Memory doesn't use battery. Unused memory is wasted memory. The best way to manage memory is to not manage memory.
Autobrightness wastes power. Constantly polling the light sensor uses battery:
How bright is it? How about now? How about now? How about now? Oooh its bright, Adjust. How bright is it? How about now? How about now? Oooh Dull. Adjust. Adjust, Adjust. Is it bright yet? How about now? Yes its bright, but is it that bright? Lets check... No its not bright. Adjust? No. Is it bright? How about now? Now? Now? What about now? Is it bright yet? getting bored of this brightness. Adjust. Is it bright?