It looks like Spotify and Apple are packing some of their own battle and the streaming music service is focused on using the weapons that Apple offers, too we can use Siri on our Apple Watch to control Spotify music, on Apple Watch and iPhone.
One of the limitations that Spotify had with regard to Apple Music was the ability to use Apple's assistant, Siri, to control the playback from its program. This is something Apple Music receives, as a native iOS service, from day one, and one of the benefits used by Apple's service over the competition. A few months ago Apple unveiled Siri for use with other music apps, and even though it took a while, Spotify now lets you use Apple Assistant on iPhone, iPad and now, Apple Watch
You should update your Spotify app to the latest version available in the App, and without doing anything else you can tell Siri directly on your Apple Watch to start playing Spotify on the watch as well as on the iPhone. All you have to do is tell Siri what you want to do on Spotify, because if you don't, by default, it will use Apple Music
For now, and although in some places you can learn the opposite, when it does not work on the HomePod. We don't know what's going to happen and Sotify will simply update its system, or if Apple doesn't allow it in any way. Gradually, it seems that Apple Music's benefits over Spotify are getting shorter, which is great news for users who will be able to choose the app they like best without losing performance.
