Even if you are highly paranoid and suspect that the encoded formats might contain something untoward, you can always convert to WAV and recode back into your chosen lossless format using software you trust. While it's true that the files (and even you, the individual purchaser) might be identifiable via the metadata, you can easily examine that metadata, rewrite what you want to retain and delete anything you don't like.
What is more interesting is the science of steganography – the embedding of data covertly within a sound or video stream. Such a process is likely to withstand multiple generations of conversions through lossless formats but may well be destroyed by one generation into the MP3 or AAC space. Such conversions are, after all, specifically designed to remove non-audible data.
The sure indicator of the existence of such hidden data that might identify the purchaser is if you and I buy a nominally identical product yet there are unexplained file differences between the two. The oddly named OpenPuff software is great fun to play with.
So there might yet be a useful purpose yet for those lossy formats
Hey, we aren't all so computer savvy.