The pure doses entrain the brain into a different state of mind. I think they're meant to be used as a tool to access the different levels of consciousness for other purposes (study, sports, creativity, sleep, meditation, etc.), and as such, the effects may not feel as profound as the drug doses. Many of the other doses will have some of the "pure" brainwaves mixed in (i.e., an antidepressant dose likely would have beta waves to increase energy and concentration and gamma waves to to improve mood to a happier state).
There's plenty of info on the internet about what the individual brainwave frequencies do, and how they can be utilized, but I've included a generalized summary here for convenience.
ALPHA: state of relaxation. This is the usual state when daydreaming. Good for meditation/stress release
BETA: awakened, energized/focused state. This is the usual state when awake. Good for concentration and peak mental performance
GAMMA: state of higher mental processing and optimal
