The bottom line for me is, just as Sub Club has ultrasonic, masked and experimental versions, that I would like to see them create an effective separate version that can be run with the most minimalist tech available, which is the phone with that tiny speaker. Not to limit the tech, but to make it as broadly accessible as possible.
With that being said the majority of my listening gets done from set-ups I have created using mp3 players attached to wired speakers. That works really well for me.
I don’t ever listen from headphones or earbuds because I find them uncomfortable, though I know for some people that is the main mode of listening, and it works really well for them.
I guess, too, I am kind of obsessive about maximizing listening time and try to find ways to do it. Often just the phone with the little speaker is the easiest, most accessible way.