This is a very good question. I have been moving slowly toward the pov of view that for most people studying these lower yānas is a complete waste of time. Oh, it can be useful to study a bit of Abhidharma because it helps contextualize mandala practice, and Madhyamaka does help cut through intellectual proliferation, properly studied and absorbed. Studying a bit of Madhyamaka helps one avoid the pitfal of crypto-advaita.Bhusuku wrote:And if Dzogchen contradicts the sutra/tantra teachings even on such basic buddhist doctrines, what is actually the use of studying sutra teachings at all for someone who's mainly interested in Dzogchen? I mean, isn't it actually a waste of time studying Abhidharma, if later on you realize that the Dzogchen teachings have a complete different POV on many Abhidharma subjects? The same applies for studying Madhyamaka: why waste many years to gain an in depth understanding of the two truths if later on you realize that there's only one truth in Dzogchen?
Also places where Dzogchen differs from sutra and tantra will not be readily understood if one does not have at least some superficial familarity with them.
You don't really need to study all this sutra stuff to understand Dzogchen, and as far as Tantra goes, anuyoga is sufficient. On the other hand, also a practitioner needs to understands that nothing really limits their practice to so called "Dzogchen practice" -- anything at all whether from Buddhist or non-Buddhist sources like Yoga, etc., can be incoporated into Dzogchen practitioner's life. One can even participate in a non-Buddhist religion, if for some reason that is necessary.
I personally think one will understand Dzogchen much better if one is grounded in sutra and tantra, but no, it is not completely necessary to learn these things. Understanding the five elements, three gates, emptiness, and bodhicitta are about all one needs at bare minimum. That, and a realized Guru -- and those are in rather short supply.