However, very experienced practitioners of meditation are able to enter a Delta state and maintain consciousness at the same time. Yoga nidra or “yogi sleep” is a sleep-like state which yogis report during their meditations. This lucid sleeping state is among the deepest possible states of relaxation while still maintaining full consciousness (“super-conscious mind”). In this state, experienced yogis are able to regulate their body temperature and heart rate.
Brainwave entrainment music can be used almost anywhere and anytime, making this mood and self-improvement method versatile and flexible enough to do at work, while traveling, or at other times during the day. When used in the workplace during short rest periods, brainwave entrainment techniques can enhance concentration, communication, and work productivity.
This is an extreme example, naturally, but the idea holds true even in situations that are not as extreme. This ties in very closely with Point #4 above. When you’re wishing to combine meditation and brainwave entrainment, if you’re practicing a meditation technique but not really paying attention to what you’re doing, or perhaps you are performing the technique wrong, whilst allowing your mind to drift off to wherever it takes you, it should come as no surprise that the entrainment track is not helping you achieve a state of meditation. That’s because in fact you aren’t really trying to enter meditation or because you’re specifically engaging in activities that prevent you from getting there.
No, it isn’t, at least not in the way these people are thinking. Neither would any other entrainment product you could purchase for that matter. Part of the problem is the proliferation of utter nonsense about brainwave entrainment one can read all over the internet. There is one site in particular that comes to mind, and the contents of that site are often copied by other websites. It is a list of Hz frequencies with their corresponding (alleged) physical effects. The list runs on for many pages. I won’t bother with the link because you can Google it and find it for yourself if you feel the need for a good laugh, but here are some examples regarding meditation and brainwave entrainment from this site:

The functional role of neural oscillations is still not fully understood;[6] however they have been shown to correlate with emotional responses, motor control, and a number of cognitive functions including information transfer, perception, and memory.[7][8][9] Specifically, neural oscillations, in particular theta activity, are extensively linked to memory function, and coupling between theta and gamma activity is considered to be vital for memory functions, including episodic memory.[10][11][12]