I have loads of Pure DSD and I enjoy it. It is a whole different thing to upsampled redbook!
Upsampling PCM redbook files (which is all PTcyap has) to DSD is an abomination in my book.
1) Redbook is just not worth converting to DSD it is too low res to bother with. Better to enjoy it for what it is. Nothing wrong with it, given a good recording and mastering and a nice DAC.
2) No conversion of PCM to DSD is lossless.
3) I don't think PCM or DSD is inherently superior to the other, but better not to mess with mixing them as this is always detrimental to the sound quality.
4) I can't believe in this nonsense of 'upsampling' anything anyway. You can't get more out of anything than what was originally in it. Oversampling in a DAC is a whole other kettle of fish. People often confuse/conflate it with upsampling. The former is valid the latter a pipe dream.
5) There is a theoretical reason to upsample DSD64 to Higher DSD rates. It possibly pushes the inherent DSD noise even higher above the so called human hearing limit. This has a potential to improve the quality of the audio in the hearing range.