A popular opinion in the brainwave entrainment community is that listening to isochronic tones without music produces a much stronger effect.  However, in the study by Doherty, Cormac. “A comparison of alpha brainwave entrainment, with and without musical accompaniment” (2014),  it was concluded that brainwave entrainment was equally effective for isochronic tones, both with and without music.
Hemispheric synchronization: Whether it’s optimal or suboptimal to operate in a state of hemispheric synchronization remains unknown. Some speculate there are numerous benefits of brain waves operating in “sync” as a result of entrainment. There may be an increased communication between the right and left hemisphere of the brain – which could improve certain functions. However, it is also important to realize that increased hemispheric synchronization may not be as beneficial as many have speculated.
I was diagnosed with “acute high anxiety, major clinical depression,and ptsd” 16 years ago. I have clinically addressed these disorders with a number of medications, which none have helped. I am so lucky I have found this simple easy to practice method of practice, that I have found these beats and tones so essential that I indoctrinated them into my daily life, and have come to the realization, that someday very soon I will awake and will not suffer from these burdens these disorders ever again.
So what happens when the mind is entrained with a sound or vibration that reflects the thought patterns? When the mind responds to certain frequencies and behaves as a resonator, [there] is a harmonic frequency that the mind can attune to … slower tempos have been proven to decrease heart and respiratory rates, thereby altering the predominant brain-wave patterns.
But again, when it comes to subjective experience, and mental evolution, I would have to caution you to take what anyone says with a grain of salt.  Obviously people want to sell these products.  There are some good ones out there and there are some bad ones out there.  There are differences in quality, as well as differences in intent with how the audios are to be used.

it says the following: “Running a delta sleep session throughout the night is not recommended as it can interrupt the normal sleep cycle”. I’ve been looping pure delta isochronic tones for about 5 days now, and have had quality sleep. Should I continue looping delta or should I let the videos play out without looping them? Will it will harm my health to do loop delta while I sleep?

Theta waves have a frequency between 4 and 7.5 hertz, making them slower than more wakeful alpha but faster than the dreamless slumber of delta. Theta brainwaves are the frequencies of nighttime dreams and REM sleep when the brain goes through bursts of activity and eye movement. People also experience theta waves in a state of light sleep, deep relaxation, during meditation and prayer, and when daydreaming. Theta waves produce an experience of inward wakefulness where we become disengaged from the outside world while engaging in inner activity. At the lower frequencies of theta, sleeping states are experienced, and at the higher range of frequency, awake relaxed states are experienced. 
There is a certain point where the promised benefits of brainwave entrainment become more esoteric, and based on internal, subjective experience of oneself.  A few examples would be that listening to brainwave entrainment on a regular basis helps to increase one’s self-awareness, or that it increases mental “sharpness”, or helps to heal emotional trauma and increase your tolerance of stress and negative emotion. 
According to both observation and research, after a series of brainwave entrainment practices, the brain learns how to state change. This enables you to achieve certain brainwave effects in the absence of entertainment. Additionally, research shows that children are usually in the Theta stage and this in itself could provide a detailed explanation for their ability to learn fast and remember what they have learned. We can take advantage of this effect and use Alpha and Theta waves to reduce learning time in adults.
Entrainment is a term originally derived from complex systems theory, and denotes the way that two or more independent, autonomous oscillators with differing rhythms or frequencies, when situated in a context and at a proximity where they can interact for long enough, influence each other mutually, to a degree dependent on coupling force, such that they adjust until both oscillate with the same frequency. Examples include the mechanical entrainment or cyclic synchronization of two electric clothes dryers placed in close proximity, and the biological entrainment evident in the synchronized illumination of fireflies.[13]