I actually do! I like using the BGM feature actually. Sometimes I use it myself and try to find ones that benefit the chapter, whether it be actual instrumental tracks (like a tv show or movie's production music/score), or ambient sounds like the rain or the neighborhood. And with my cartoon works (including the novels), its very fitting to add some in at least a story or two.
I know its not EVERYONE'S ideal thing to hear when reading, but for some who just like a little fitting music to go along with their experience is quite nice every now and again. I just wish that there were more options to insert BGM like using songs from YouTube. For my works especially, SoundCloud doesn't always have the tracks I WANT to add, so I always have to go for a.... close-second version to say the least. Plus, there's always an option to turn it off or let it auto-play if you're just reading it silently and you AREN'T on mobile.
I'm not always on mobile, but its a nice surprise to hear a song that fits the mood of a story's certain chapter or comic page.