maybe it could be interesting to allow playing a segment of a song, from a game owned by each user, without auto-play; that would obv entirely depend if devs and publishers of games would allow "freely" that kind of use (if that would cost valve something, it would be a worthless feature for them)

auto-play should not be available by default (it should be a choice of each user if music or any media plays automatically, independently from the intentions of the one that placed the content).

imo, an additional, more simple option, would be to improve how music or media players from youtube or any other sites that already has music can be used. maybe steam could offer their own media player, and allow streaming to it from other sites.

adding music to the point shop makes no sense imo, because points lack actual value and items in the point shop cannot be traded like the items from the marketplace. that means the music licenses would need to be paid by either valve or the devs that would be willing to share it there, and no dev would: if you check the "startup animations", what most of them have in common (that arent from valve) is they look more like mini-ads or commercials, rather than trying to present steam or steam deck logo in an original way; it branding. if audio was allowed to be used for profiles or anything else, most publishers and devs would try to use it that way: to at least include the name of their product or brand, so casual listeners would have it in mind.

so, thats why i think is not a good idea. we already have too many ads everywhere.