Tournedos - I do not understand how Apple makes money from their lossless format? iTunes is free, the conversion program included is free. You pay for your computer, but you can use iTunes non non-Apple computers, and the worldwide majority of iTunes users do not use Apple computers.
WAV or AIFF is full-file, while FLAC, Apple lossless and other lossless formats reduce the size of the originating file, without losing any information. Whether you want to use Apple lossless is another matter. Many suppliers of high-resolution files provide these in FLAC, WAV, etc - and then leave it up to the users whether they wish to convert the files to another format, for instance one of Apple's, or any of the hundreds of others available, for free or purchase.