For some definitions of "all" I agree. i.e. for Hifi quality Stereo Music to end users where file size and bandwidth are not so important, yes fine, but in situations where space or bandwidth are limited / expensive, AAC can achieve transparency at well below 256kbps with most music, to most people, in which case it would often be overkill --especially for Audio Books, lectures, plays or other mainly speech content... conversely for 5.1 or greater multi-channel audio it's often insufficient.
