Some people deny there is any such thing as “spiritual”. Atheists, secular humanists, etc., do not as a rule accept the concept of the existence of things “spiritual.” For them the benefits of meditation are largely physical and/or emotional in nature. It is not my intention to dispute or attempt to change their views here. What I can say is that they are free to skip over any mention of things spiritual and focus on the physical/emotional aspects. Meditation is a broad enough discipline to encompass all these areas of our existence.
Both brainwave entrainment and neurofeedback deal with brainwaves, but the similarity stops there. Entrainment pushes your whole brain into a pre-determined state, while neurofeedback teaches you how to move specific parts of your brain on your own. It is the differeence between forcing the brain into a given position, and skills building so you can move it there yourself.