One key thing that HomePod has in the competition: the synergy of transmission of services. It is an important advantage in the heart of the Smart Smart Speaker. While both Amazon and Google have their own transmission options, they are pale compared to the best services, so that third parties are really the way to go.
Amazon just added another key offer to your arsenal. Tidal, the music streaming service that Jay-Z has built, is now available on Echo devices courtesy of the Music Skill API recently introduced by Amazon. The move is likely to be more a blessing for Tidal than Amazon, of course, but the more options it is better, of course.
The service has been making aggressive efforts to make its way to more devices, including the recent addition of a Samsung Wearable application. Tidal is clearly looking at the strategic reach of Apple's main competition. The enemy of my enemy is my hardware partner and all those good things.
The new ability allows you to configure Tidal as the default Echo transmission service, provided you have a premium account.