I do not believe that doing brain entrainment while you are asleep is good. During sleep, you slip into alpha, theta and delta progressively. If you put the sleep track on repeat, you will probably get alpha or theta entrainment over delta. You are also meant to have a total rest during sleep, not interference from other sources.

I sleep with ear buds and pull the cord above my head, so I do not break them with my arms as I was used to a couple of years ago.