I have ADHD (professionally diagnosed as an adult) and basically cannot focus without music. I complained at work about endpoint management software that was interfering with my music player and was told I didn't need to listen to music while working.
I WFH so I just found another way to play music, but it was tempting to point out to my boss (who I otherwise quite like) that he had just told me that I shouldn't be using a reasonable accommodation for my disability that costs the company nothing, lol.
Not to excuse these dark patterns from shitty products that can't get revenue without tricking people, but privacy.com lets you set up single-use credit cards with e.g. a $1 lifetime limit. This is my go-to for places like this if I really, really want to try it.
You might enjoy the binaural beats and ambient radio on https://ambiph.one as a free alternative (disclosure: it's my site). Not as science-y as brain.fm but it helps me a lot with focus
I’ve measured the work I get done over sprints where I listen to brain.fm and where I don’t, and I usually get 2-3 more cards done of weeks that I do.
Not a scientific measurement, but it is what it is.