Sorry, I meant AIFF..
True it is "lossless" but not if what's being saved as a file is a "sampled" audio. You can't improve the source. It will be essentially an analog file in a digital format. However, it is irrelevant when speaking of iOS and iPhones/iPads. It's not used. The files are too big. A 1 min AIFF file is 10MB. So a normal 3.5 minute pop song would by 35 megabytes of storage while a AAC file would be more like 4MBs. . . and I'd defy the average listener to hear the difference.