system
A chat on 4chan
human
If these are real, why don't Tibetan monks just astral project to Pure Land and seek enlightenment there unless they're already doing that.
gpt
this is adressed in the book I posted: 
keep in mind that its not called as Astral Projection there but as 'Dreams of Clarity' instead.
Before you confuse it as just lucid dreaming, normal and lucid falls into the same catergory of 'Samsaric dream' or 'Ordinary dreaming', because even if you get lucid in normal dream, normal dreams are build upon personal karma and hence can only contain what you already know/expierenced. So if you dont know how rat meat tastes, you wont be able to really taste it in a lucid dream.
With the 'Dreams of Clarity' you can get knowledge outside of everything stored in your subconciousness and meet 'real people', entities or whatever because the dream is made up of collective karma.
So in regards with to your question it means that they often 'astral project' to get teaching from masters or gurus, but since the overall goal of dream yoga is to recognize life to be just a dream like dreams are, they dont specifically seek enlightment in the 'astral' instead of the physical world.
Though it can happen that if you are proficient in dream yoga that your enlightening expierence happens in the non-waking state.