I still don't know why any iPhone people have Spotify over Apple Music
Because the rest of the world isn't the US.
Where I live, Sweden, things like the Homepod are still not for sale officially. That's any version of the Homepod, ever. Siri is pretty terrible in Swedish as well.
Apple fans in places like the US don't seem to realise that Apple treats most of the rest of the world as second class citizens. Whenever any new service comes out from Apple my automatic reaction is to not expect to see it for at least a year.
Whereas Spotify is here, it works and is supported by pretty much all my devices, something Apple has failed to do as they won't even sell the device to replace my Amazon Echo.
And yes, I could do some kind of grey import, but you kind of get used to such things not working too well as they tend to rely on services that just don't exist yet and/or are geolocked.