About the phenomenon of people having particular subconscious responses to auditory stimuli? I wholeheartedly believe it - I experience it, I know countless other people experience it, and it is too obvious not to exist, as visual, olfactory, and other sensory responses of a similar kind exist.
But about the ASMR videos on Youtube and other sites? Man, what a creepy rabbit hole to walk into.
I find them extremely, absolutely creepy, and unsettling. It's usually a young woman, talking in a sensual voice, flirting with the viewer, coddling him or her in a way that to me feels like an unholy, incestuous combination of trying to be a mother and a lover at the same time. They also often have this weird sadness to them, as if they were far from the loveful person they try to be, instead of hurting with extreme loneliness. But I might be reading too much into it.
I can't help but imagine a creepy stalker, obsessing over the girl, religiously watching every video to hear the person speak to them as if they were lovingly caressed by her after a tiring day - and I know that “stalkers” are neither the target nor even the main audience of ASMR videos. It's something that I find extremely dirty and wrong - and at the same time, I find prostitution completely acceptable and not immoral in itself (although infidelity is another can of worms). Prostitution at least is honest.
When it comes to videos with just ambient sounds - a hair buzzer, rustling leaves, bubble wrap, plastic bags, even paper being ripped (although I absolutely hate that particular sound, kinda like chalk on a blackboard for other people - and chalk I don't actually mind) - they're absolutely fine and I don't see a problem with them. I mean, “sounds of nature", with chirping birds, rain, and trees rustling in the wind have always been a staple of relaxation.
But please don't make me think of those other ones.
Below is one of those ASMR videos about ASMR Relaxing Crunchy Sounds, I think you will love it.