I find it so odd that people then to streaming services for stuff like this. I have a dedicated white noise machine, and when I travel, I use the white noise (bright noise actually) built into the iPhone.
Relying on an external hosted service would never cross my mind, and surely wouldn’t be something I go to on a daily basis.
It's not odd if you aren't the type who frequents hacker news. We are, after all, very much in a bubble here.
You might find it interesting that there's an entire genre of youtube video that's designed to just be chucked one by one into slideshows for elementary school teachers to use as their lesson plan. Including videos that are just "2 minute timer for kids!"
e.g. https://www.youtube.com/@Ask.the.Teacher
"Independent Reading: Count Up Timer for Classrooms": https://www.youtube.com/watch?v=AfLfJtVeME8 straight up just stock imagery and a timer lol