I initially agreed with you but after watching the demo, it has some game-related features that I'd imagine would be hard to implement in other applications such as:
Choosing the length of looping songs from 15, 30, to and hour which is ideal for background music.
Spoiler Free options where you can choose certain games to avoid being recommended/listen to.
Don't have Nintendo Online (only got it for Splatoon 3) but this product should've come out years ago when they introduced Nintendo Online.