If you're in a DM or a group chat, you may not hear "You should listen to X by Y" but rather "Check this out: https://open.spotify.com/blah"
At my current workplace and a previous one, both had Slack channels for sharing music and they were 99% Spotify links.
Partly because of genuine Spotify usage but even not using Spotify at the time, I would find the Spotify equivalent for my own recommendations (to reduce friction for the majority so they'd be more likely to actually listen to the recommendation)
Presumably for those few users not using Spotify, rather than having to find the equivalent song via text search, which may or may not contain a result for Provider Z, this service straight up just converts the Spotify link you've been given into all of the other provider equivalents.